This easy keto fish pie is comfort food at its best. It has a deliciously creamy filling and a cheesy cauliflower mash topping.
Fish pie is a classic British family dinner and one of the first dishes I learned when I first moved to London.
The traditional recipe consists of a variety of fish in a white sauce that is topped with mashed potatoes. You then bake it in the oven until the topping is crisp and golden.
It is very simple to turn it into a proper low carb fish pie. I got my inspiration from two different recipes in Vickie De Beer's amazing Low Carb Diabetes Cookbook.
The most important change is to substitute the potato mash with mashed cauliflower. I promise you won't taste the difference. My daughter even declared: "I love the potato mash!"
We make this pie regularly and everyone always wants to come back for seconds.
🌟 Why You'll Love This Recipe
- Creamy and comforting
- Ready in just 1 hour
- Freezes well - great for meal prep
- Keto friendly - only 8.1g net carbs per serve
Here are the ingredients you'll need:
For the filling
- White fish fillets. I used hake and cod.
- Onion. Finely chopped.
- Garlic. Fresh is best, but you could replace it with garlic powder.
- White wine. Use a dry wine. Can be substituted with fish stock, vegetable or chicken broth.
- Heavy cream. This is double cream here in the UK.
- Zucchini. Should be grated. This thickens the sauce.
- Lemon zest.
- Fresh parsley and chives.
For the mash
- Cauliflower. Make sure it is very fresh. If you only have frozen cauliflower or cauliflower rice, squeeze out all liquid after cooking with a cheesecloth or dish towel.
- Sour cream or cream cheese
- Cheddar cheese
- Nutmeg and salt
All amounts and details are in the recipe card at the bottom of the post.
This is a very simple recipe that even beginners can master easily. Here are the basic steps:
Step 1: Steam, boil or microwave the cauliflower until soft. Use the tips in my post on keto mashed cauliflower. Drain well.
Step 2: Put the cauliflower florets in a food processor. Add the softened butter, soured cream, cheddar, chives, nutmeg and salt. Blend until smooth. Set aside while you make the filling.
Step 3: In a large skillet or frying pan, sauté the onions and garlic. Fry until soft and translucent over a low heat.
Step 4: Add the white wine. Cook over a high heat until reduced by half.
Step 5: Add the zucchini, cream, lemon zest and herbs. Season with salt and pepper and let simmer for a while.
Step 6: Put the fish fillets in a casserole dish and pour over the sauce.
Step 7: Put the fish fillets in a casserole dish and pour over the sauce. Spread the cauliflower mash on top and bake.
Serve with a crisp green salad, a side or green beans or enjoy all on its own.
It is essential that the cauliflower is very soft, but not watery. If you have steamed it, pat it dry. If you have boiled it, drain the water and then put it back in the pot. Let any residual moisture cook off, without letting it burn.
Any white fish works, as well as salmon or prawns or even lobster. You can also try a smoked fish.
Of course. Simply fill into single serve ramekins.
For a dairy-free version, use a dairy-free cream instead of the heavy cream. Use olive oil instead of the butter in the cauliflower mash and add either a vegan cheese or nutritional yeast for a cheesy taste.
Single cream (or half and half) is more watery than heavy cream or double cream. I don't recommend it.
Refrigerator: Store Keto fish pie in the fridge for up to 3 days.
Freezer: Freeze for up to 3 months. Thaw overnight in the fridge, the reheat in the oven or in the microwave.
If you love fish recipes as much as I do, also check out my Low Carb Keto Fish Tacos and this pesto salmon!
More easy dinners
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Low Carb Keto Fish Piefrom Sugar Free Londoner
Note: The servings slider only changes the first amount in each line and not any subsequent amounts. Please make your own calculations where necessary. ***As an Amazon Associate I earn from qualifying purchases.
For the filling
- 1 onion chopped
- 2 garlic cloves chopped
- 1 cup dry white wine (250ml)
- 1 cup double/heavy cream (250ml)
- 3 medium zucchini 550g, grated
- grated lemon zest from 1 unwaxed lemon
- handful of fresh parsley and chives chopped
- 1.75 lb hake and/or cod fillets (800g) without skins
- pepper and salt to taste
For the cauliflower mash
- 1 very large or 2 smaller cauliflower heads 700g
- 3 tablespoon melted butter 40g
- ½ cup soured cream or cream cheese, (125g)
- 1 cup cheddar shredded (125g)
- 1 tablespoon chopped chives
- ¼ teaspoon nutmeg
- salt to taste
- Separate the cauliflower into florets and steam/ boil/ microwave until soft. Follow the tips in my keto mashed cauliflower recipe.
- Add the butter, soured cream, cheddar, chives, nutmeg and salt. Blend in a food processor or with an immersion blender until smooth.
- Preheat oven to 200 Celsius/400 Fahrenheit (electric) or 180C / 360 F fan.
- Fry the onions and garlic in olive oil over a low / medium until soft and translucent, around 3 minutes. Do to burn.
- Add the white wine. Turn up the heat to high and reduce by half.
- Add the grated courgettes, cream, lemon zest and herbs and simmer for 5 minutes. Season with salt and pepper.
- Put the fish fillets in a casserole dish and pour over the sauce.
- Spread the cauliflower mash on top and run a fork over the top to make lines.
- Bake for 40 minutes or until the top is browned.
- Sprinkle with some fresh parsley and serve.
I made both our fish pie and your fish cakes for my daughter in law who is ill and special dietary needs. After four years I persuaded her to try fish and she loved it. Thank you it's a hit.
Do you have a sauce suitable for fish cakes too? It will be frozen fish cakes so if a sauce is ok to add to a container in portions it will help.
I had to tweak the recipe slightly as one of my guests is allergic to alliums, so I replaced the onions with celery and fennel. Even so, it was delicious. The whole thing got polished off. It was quite a lot of work, so in advance of next time, I made the sauce, and the cauliflower mash and frozen them, so will be easy to put together.
Fish pie is something I have never had before. Loved the taste, my hubby did not! I went back for seconds! The cauliflower mash is something that I will have to get used to but it was good! I used cod for mine but if I can find haddock or rockfish I will try it with that next go. I think I will make the mash separate from the fish next time and see what hubby thinks of it then.
If I used half an onion do you think that would cut the carbs? My daughter is trying 20 carbs a day. Thank you.
Yes, it would. Onion is fairly high in carbs. Replacing the wine with more stock will also lower the carbs.
Hi Katrin, The recipe looks great but I have IBS and Diverticulitis and follow the Low Fodmaps diet which really helps. I’d love to do Keto but cauliflower is a no no as it’s high Fodmap and it’s used as rice replacement in so many savoury dishes…. Do you have any suggestions as to what I could replace it with?
And is there any other flour except almond or coconut that could be used in the baking for the same reasons. I think 24g almond flour is the max in one meal! Many thanks
You could use rutabaga or celeriac mash instead. Both are higher in carbs, but you may tolerate them better. Instead of almond flour, a 50/50 mix of sunflower seed flour and sesame seed flour usually works well. Coconut flour cannot be replaced 1:1 because it's more absorbent than any other flour I know. Hope this helps!
Can you freeze this?
Yes, this fish pie freezes well.
Hi, just trying to work out the nutrition values. What would you roughly say the grams are per portion that you’ve supplied? I know you’ve put that there are 6 portions.. but what was the original weight so I can add in my side?
I’ve tried and was so lovely by the way,
I also was a little naughty and added crispy bacon bits, and also tried an alternative method with mashed butternut squash one time as I didn’t have cauliflower and was also yummy.
Hi Alex, I'll measure the ingredients when I next make the recipe. Your variations sound delicious!
this is absolutely delicious. Neither of my teen sons are fans of white fish normally - find it a bit dry and not filling enough. My youngest pulled a face when I said we were having fish for dinner but...absolutely lapped it up and had the leftovers for breakfast! Nb I had only one smaller cauliflower and added some (also low carb) turnips to the mash - made for the best tasting and textured low carb mash ever (1 cauli, three small turnips). I'll definitely be making this again.
I was just wondering it seems you don't coo the fish first would it work if you added the fish to the stock/wine or in the last 5 mins with the other filling ingredients? Or would this make it mushy or change the flavour too much?
I've never cooked fish let alone a fish pie but this sound super yummy I'm hoping you can convert me
You can probably add the fish in with the other ingredients for the last 5 minutes it you prefer that, I don't think it will make much of a difference. It will cook through in the oven though!
Can’t wait to try this, sounds delicious. How do you reheat the leftovers? Or is it better to eat them cold?
I just stick it in the microwave! Or re-heat in the oven, just like you would a regular fish pie 🙂
Cant wait to try this recipe ive been needing this in my life since doing keto ha!
is sour cream better than cream cheese? or what did you use?
I used sour cream, but both will work.
I made this for the second time, this time with broccoli instead of cauliflower. Both times, it was absolutely delicious and so comforting today, on this colder Spring day.
It was freezing here today too!! Glad it hit the spot 🙂
I don’t want alcohol in my home, what can I use as a substitute for the wine?
I would just use vegetable or fish stock instead.
I don't have alcohol in my house either. I will use de-alcoholised wine when I make this. I did that when I needed wine for a special spaghetti Bolognese which turned out really well.
I have some cod in the freezer and didn't know what to do with it. Now I know what I'm going to do with it.
Can you tell me what size casserole dish you used?
I live in Arizona... USA... Thanks for the recipes you have converted to low carb.
Hello there, I used a 13 x 9 inch casserole dish. Hope you'll try the recipe!
I found your site at Xmas and decided I was going to supplement your low carb recipes as an evening meal with my milkshake diet, after a week of trying your very tasty recipes I got rid of the milkshakes and went with just your recipes, I’ve lost 14kg since Boxing Day, I’m a definite convert, your recipes are tasty, easy to do and very filling!!!!!! Your fish pie is most definitely my favourite however (the point of this message) can I use single cream instead of heavy cream?
You must be so happy - 14 kilos, amazing! I think you can use single cream, but as it's more liquid you may want to use a little less / reduce the sauce a bit more to make up for this.
Hello Katrin, I am new to your site. I was looking up desserts and found this one later. You got me at comforting and fish. We liked it but I think that the fact that my fish was frozen, it was watery. I think my second version will be better. I am writing to you from Quebec, Canada. Cheers to your day. Julie
Hi Julie, I'm sure you can use the same fish again, just make sure you reduce the liquid more before putting it in the oven!
Hi again, I forgot to mention that I have a keto lifemeal now. I would love more one pan meals. Bye for now!
I have never heard of fish pie, but it sounds really good. I love fish!!! I will be trying it this week.
It's a British staple - made low carb. You'll love it, it's so tasty 🙂
Hello Katrin! I love your recipes and I'm very new to your site. I am writing you from California in America! It seems that I've seen in other recipes from you that there was a button to push to change the measurements from Metric to Imperial. Am I correct or confused? Lol! I was hoping to find the conversion button, but wasn't able to find it. Not a huge crisis, but I was wondering. Thanks much!
Hi Christina, glad to have you here! I use the same recipe plugin for all recipes, so all should have the same features! I think the toggle is only there to change the amount of portions. Tell me - are you looking for ounces?
Can I ommit/sub the white wine?
Sure you can, you could use vegetable or fish stock instead 🙂
How about substituting broccoli for the zucchini? will that affect the nutritional number by much?
The great thing about zucchini is that it has a very mild taste. It gives the sauce substance and thickness but does not overpower it. I think you would be able to taste the broccoli. That's not a bad thing if you like broccoli and it could definitely work. In terms of nutrition, I think it would not make much difference. Both veggies are really healthy and low in carbs.
Me likey, likely - cannot wait to wrap my laughing gear around a heaped spoon of this luscious sounding fare. Thank you for the inspiration on this great Monday.
Davodourian, you lovely lady, you'll enjoy this pie immensely. Hope it will brig back memories of good old Blighty 🙂
I made your fish pie on Friday for lunch. It was super. Am still eating it today Sunday. I used leeks which went well with your recipe. Thank you for posting this. Am Looking forward to trying more of your recipes.
Thank you for your comment Mary. I can imagine that leeks would go well with the pie, sounds great.
I'm more of a Shepherd's Pie person, but this looks like i need to give it a go. Can you use single cream instead of double cream?
Of course you can! I'm sure it would work well, too
Now I know what I'm making for dinner tomorrow!! Looks good...
Glad I put it out there 🙂 Hope you'll like it!
you should definitely post more savoury recipes 🙂 I really liked it..used some salmon, haddock and hake and also added hard-boiled egg. Thanks for the inspiration
Brilliant! What a nice twist to add the egg. It's often used in fish pies.
Thank you for this recipe! We had the most amazing dinner last night. And plenty of leftovers. This dish is filling!
So happy you all enjoyed it. And you are right - this dish is filling. In all the best ways!