Your guests will never guess this mixed berry pie is low carb and free of added sugars! This keto pie has a super fruity berry filling and and a crispy fathead lattice top.
There’s nothing like a good berry pie, no matter what the weather looks like outside! I always have frozen berries at home - blueberries, raspberries and blackberries. I like to use them in my keto granola recipe for breakfast and of course they are invaluable for blueberry coconut flour muffins!
I've been wanting to make a Keto berry pie for a while. You all know I'm a big fan of fathead dough - I love that it works in both sweet and savoury recipes, from keto cinnamon rolls to keto pot pie. I think the fathead dough works really well on top of this pie, it's lovely and crisp.
You could make a full pie crust top if you prefer, but I think the lattice weave makes it look super pretty. If you go for the full pie crust top make sure you pierce two tiny air holes in the top with a sharp knife to let the steam release.
This Keto Skinny Berry Pie has all the taste and comfort of a good berry pie but I'm calling it my cheats skinny version because it doesn’t have a base. I was after a dessert that's satisfying yet not incredibly heavy and filling. I guess you could say it’s a cross between a crumble and a pie. A crumble base and a sugar free lattice pie top.
How to make a keto-friendly skinny mixed berry pie:
1.) Add the frozen berries, sweetener, lemon juice, zest and cinnamon to a pan. Cook on a medium heat for about 7 minutes, stirring occasionally.
2.) Stir through the ground chia. Heat for 2 minutes then remove from the heat and allow to cool to thicken for about 30 minutes. Adjust the sweetness to taste and add more chia if you like it thicker.
3.) Meanwhile make the dough. Melt the mozzarella in the microwave on high for 60 seconds, stir with a rubber spatula and heat for another 30 seconds.
4.) Add the almond flour and egg and mix until you have a smooth dough.
5.) Roll the dough between two sheets of grease-proof paper and cool in the fridge for 20 minutes. Then cut into strips on a using a pizza cutter or sharp knife about 1 cm in thickness.
Top the mixed berry pie with a lattice and bake for 15 - 25 minutes until golden on top. Oven time will depend on the thickness of your lattice.
How to make the lattice pie crust:
First of all, make sure your dough is cool enough so it's easy to handle. You can even make the dough strips the night before and leave them in the fridge overnight.
To make the lattice top, lay the bottom strips on top of the berries then starting at one side add a strip perpendicular and just lift the bottom ones up and under.
Don’t worry about making your weave perfect with under and over too much, rustic is good!
Once the lattice is done, trim the fat head dough at the edges. Brush with a little egg white and sprinkle with low-carb sweetener.
Short on time? Simply roll out the dough and cover the pie with a basic pie crust. Don't forget to cut a few holes into the crust so the steam can escape!
How can I thicken my berry pie?
Traditionally, cornstarch or potato starch is used as a thickener. However, neither is low carb. I'm using ground chia seeds to thicken this keto pie, which works a treat. Ground chia is incredibly useful for thickening anything in low-carb cooking, from jams to sauces. You can even use it as a vegan replacement for eggs. I always keep a jar of ground chia in my larder.
I wanted the consistency of this berry pie to be more on the runny side (I'm all for licking plates!!). But you could totally double the amount of ground chia and end up with a filling that's firm and sliceable when cold.
Serve with sugar free ice cream, Greek yoghurt, whipped cream or coconut yoghurt for dairy free.
Here are some more sugar free berry dessert recipes you might like:
- Sugar Free Strawberry Shortcake Trifle Pots
- Triple Berry Sugar Free Gummy Bears (Keto)
- Keto Coconut Flour Muffins with Blueberries
Tried this mixed berry pie? Give it a star rating below!
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Recipe

Skinny Mixed Berry Pie
from Sugar Free LondonerNote: The servings slider only changes the first amount in each line and not any subsequent amounts. Please make your own calculations where necessary.
Equipment
- Pie dish (24 cm / 9.5 inch in diameter)
Ingredients
BERRY BASE
- 23 oz / 650 g frozen berries I used 200g blackberries, 300g blueberries and 150g raspberries, ***see notes
- ½ cup / 75g granulated sweetener
- 1 tablespoon lemon juice
- 1 teaspoon lemon zest
- ⅓ teaspoon ground cinnamon
- 3 teaspoon ground chia seeds
SWEET FAT HEAD DOUGH
- 1 ½ cups / 170g grated mozzarella
- 1 scant cup / 90g almond flour regular / coarse or ground almonds, use ¾ cup / 75g for extra fine almond flour
- 1 medium egg room temperature
- 2 tablespoon granulated erythritol
TO DECORATE
- ½ large egg white
- ¾ teaspoon granulated erythritol
Instructions
- Add the frozen berries, sweetener, lemon juice, zest and cinnamon to a pan. Cook on a medium heat for about 7 minutes, stirring occasionally.
- Stir through the ground chia. Heat for 2 minutes then remove from the heat and allow to cool to thicken for about 30 minutes. Taste and adjust the sweetness to taste and add more chia if you like it thicker.
- Meanwhile make the dough. Melt the mozzarella in the microwave on high for 60 seconds, stir with a rubber spatula and heat for another 30 seconds. Add the almond flour and egg. Mix. You may need to get your hands involved here!
- Roll out the dough between 2 sheets of parchment paper and place in fridge for 20 - 30 minutes to chill. Then cut into strips on a diagonal using a pizza cutter or sharp knife about 1 cm in thickness.
- To make the lattice, lay the bottom strips on top of the berries then starting at one side add a strip perpendicular and just lift the bottom ones up and under. Trim at the edges, then brush with a little egg white and sprinkle with low carb sweetener.
- Preheat the oven to 400F / 200C conventional / 180 fan.
- Bake for 15 - 25 minutes until golden on top.
Notes
Nutrition
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Kathy Kelly
I loved this pie & so did my family! I did a full crust & it came out blue from the berries. It didn't look good but tasted great! What did I do wrong?
Katrin Nürnberger
Not sure - maybe a temperature issue? If the ingredients are cold, this would give the berries more time to soak through the dough before it bakes. Or if there's a lot of liquid, it could bubble over and colour the crust.
Suzanne
I've made this delicious pie 3 times and have learned that the Chia seed amount needs to be 3 Tablespoons not 3 teaspoons.
Katrin Nürnberger
Hi Suzanne, do the 3 tbsp make the filling firm?
Judy
Can I substitute w/ powdered erythritol, if I don't have granular? If so, how much should I use? Thank you so much for sharing your wonderful recipes!
Katrin Nürnberger
Of course you can Judy, I would just use the same amount.
Heather
Made this last weekend and it was a huge success! Delicious recipe, thank you.
Katrin Nürnberger
You're so welcome! Really glad you enjoyed it.
jade
Hi, I love your recipes and am trying to buy the ingredients but I can not for the life of me find, Erythritol in Ireland in the shops. However I can get xylitol everywhere, is this a good substitute? I don't want to ruin the recipe at all so if its best I will order erythritol from abroad (I want to do it right), I know stevia is bitter so I don't want to go down that route.
Thank you very much!
Katrin
Hi Jade, you can definitely use xylitol. I don't use it much, but it has the same sweetness as erythritol. You can order erythritol on Amazon - NKD Living is a UK based brand which sells very reasonably priced erythritol.
Beverly Oliver Carr
Can you help me understand the second step? Stir through the ground chia? Then heat it? Do I just stir the chia seeds, and heat it in the microwave, or do I put it in a pan with water (?) and heat it?
Katrin
Hi Beverly, it doesn't make much difference whether you take the berries off the heat and stir in the chia into the hot berries or whether you heat the chia berry mix for another couple of minutes. Chia takes some time to expand, that's the important bit.
Patti
Also, what size pie plate did you use?
Thanks
Katrin
Hi Patti, it measures 24 cm / 9.5 inch in diameter.
Patti
Looks looks so good!!!. If I just have chai seeds, not ground, do I grind, then measure? Thanks!!!