These are the crispiest keto onion rings you'll ever find! They are ready in just 15 minutes and make a tasty appetizer, side dish or snack. Includes frying pan method, air fryer method and oven method.

Crispy onion rings are always on top of the list when I have a "junk food" kinda day. Even before I started a low carb diet, I'd reach for onion rings over French fries. They are just so much more interesting!
I think you'll love this keto onion rings recipe. It goes perfectly with keto chicken nuggets, keto hot dogs or burgers (check out my black burger buns!).
I decided to make them the old school way by deep-frying them for superb crispness.
This batter tastes very similar to one made with wheat flour because it uses my secret ingredient - whey protein isolate. It is super-fine and becomes incredibly crispy - much more than any almond flour coating!
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🌟 Why You'll Love This Recipe
- Incredibly crispy texture
- Authentic flavor
- Naturally gluten-free
- 3 cooking methods - pan-fry, air fryer and oven
- keto friendly - only 3.3g net carbs per portion
Ingredients
Here are the ingredients you will need:

- Onions - I use yellow onions because they are lowest in net carbs.
- Whey protein isolate - This should be unfavored whey protein.
- Seasoning - It's essential to use a good amount of spices to flavor the breading mixture. I like garlic powder, paprika, sea salt and black pepper.
- Egg - Just like for any regular breading, the egg is necessary to bind the breading with the onion.
- Dijon mustard - In my opinion, this tastes better than yellow mustard.
- Sparkling water - There is something about carbonated water that makes the breading lighter and crispier than if you used regular water.
- Avocado oil, ghee or coconut oil to fry. All of these oils have a high smoke point. Another option would be to use a light olive oil.
See the recipe card for full information on ingredients and quantities.
Variations
There are various types of gluten-free batters and breading. The most common coatings are almond flour, coconut flour or pork rinds plus seasonings.
For a variation, try these keto bread crumbs instead of the whey protein mixture. This breading contains almond flour, parmesan cheese and my secret ingredient - ground flaxseed. It is super crispy.
Instructions
This section contains step by step instructions and photos that show how to make the recipe.

Step 1: Slice the onions into rings.
Step 2: Place all the dry ingredients in a shallow bowl and mix. Add the wet ingredients to another bowl and mix to combine.

Step 3: Dip each onion ring in the egg mixture and then into the dry mixture to fully coat them with the breading.
Step 4: Heat the oil in a large pan until hot and bubbling. The oil should be deep enough to fully cover the onion rings.
Step 5: Carefully lower the onion rings into the hot oil and fry about 45 seconds or until golden brown and crisp.

Step 6: Remove the rings with a slotted spoon and place on a paper towel to soak up any excess fat. Repeat until all rings are fried.

Expert Tips
Here are my top tips how to make the recipe perfectly.
Coating: Use one hand for the bowl with the dry mixture and the other hand for the bowl with the wet mixture. That way, your hands won't get sticky and messy.
Frying: Coat 8 rings at a time and fry in batches of 4 to avoid the batter soaking and disappearing into the egg.
Recipe FAQs
Spray the breaded onion rings with cooking spray and air fry at 180C / 350F for 8 minutes or until the top is browned. Then flip them over with a spatula and air-fry for a further 8 minutes or until fully crisp.
The most important thing is to keep the rings in a singer layer so the air can circulate around. If you have a smaller air fryer, you'll need to cook them in 2 batches.
Yes, but they won't be as crispy as with the deep-fried or air fried method. To bake low carb onion rings, preheat the oven to 200C / 400F. Line a baking pan with parchment paper and arrange the onions in a single layer, not touching each other.
Spray them generously with oil and bake for about 10 minutes or until the tops are golden. Flip over and bake for another 10 minutes or until the keto breading is golden all over.
I don't recommend it. The rings go soft when stored. Also, they need to be fried straight after breading or the whey protein powder will go soggy.
Onions are are suitable for a keto diet in moderation. Since an average whole onion contains 11 grams of net carbs, it's important to keep the portion size low.
Regular onion rings are not keto friendly. They are coated in wheat flour, cornflour or breadcrumbs. These keto onion rings are the perfect solution for a low carb diet.

Dipping Sauces
Onion rings taste even better with a dipping sauce!
Serve them with homemade sugar free ketchup, keto mayonnaise or sugar free sweet chili sauce.
They also taste great with ranch dressing or a blue cheese dressing. For a bit of kick, choose this sriracha aioli.
Storage
Refrigerator: Keto onion rings are best fresh. If you have leftovers, store them in an airtight container in the fridge for up to 2 days. They will go soft.
Reheating: To crisp them up again, reheat in the air fryer or in the preheated oven at 200C / 400F for about 5 minutes.
The recipe is not suitable for freezing.
Related Recipes
Here are more veggie based keto appetizers to try:
- Crispy Baked Keto Zucchini Fries40 Minutes
- Cauliflower Popcorn45 Minutes
- Spinach Balls - Keto Appetizer30 Minutes
- Low Carb Keto Falafel40 Minutes
Tried this recipe? Give it a star rating below!
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Recipe

Keto Onion Rings
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.
Ingredients
- 120 g onions actual onion rings - 3 onions (170g) and I discarded the ends and tiny bits in the middle
DRY
- ยฝ cup whey protein powder isolate, 50g
- ยพ teaspoon garlic powder
- 1 teaspoon paprika
- ยฝ teaspoon flaked salt
- ยผ teaspoon black pepper
WET
- 1 large egg
- 1 teaspoon dijon mustard
- 1 tablespoon sparkling water
- Oil to fry. Avocado ghee or coconut are best. I used 2 cups.
Instructions
- Use a fork to steady the onion. Slice into 1 cm rings. Remove the skin and separate the rings. Discard the ends and the small rings right in the centre.
- Heat the oil in a 18 x 9 cm saucepan until really hot and slightly bubbling. The oil should be deep enough to fully cover the onion rings. I used 2 cups.
- Place all the dry ingredients in a bowl and mix. Add the wet ingredients to another clean bowl and mix to combine. Dip each onion ring in the wet and then into the dry to fully coat and place on a wire rack. Coat 8 at a time and fry in batches of 4 to avoid the whey batter soaking and disappearing into the egg.
- Carefully lower 4 onion rings at a time into the hot oil and fry about 45 seconds or until golden and crisp. Remove the onion rings with a slotted spoon and place on kitchen paper to soak up any excess fat.
- Repeat for all the remaining onion rings.
Nicole
Du รคr fantastisk och dina recept รคr underbara!!! Tack fรถr ditt jobb!!!
Terry
I โค๏ธ onion rings and canโt wait to try this recipe! I have loved every recipe that I have tried from Sugar Free Londoner so I already know that these will be yummy!
Got a question thoโโฆ..
Can these be done in an air fryer?
Ruthanne
Absolutely delicious!!! I have been craving salty and crispy and keto..ahhh! What's not to love? I confess I ate the all the rings from an entire onion. No sharing. ๐
Llama
WOW...these are AWESOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Better than any fastfood onion ring I've ever had!!!!!! The prep was a bit tedious but they fry up in 45 seconds (set deep fryer to 375 with coconut oil) and they're ready! Made them for the second time this afternoon. Thank you, thank you, thank you for such an incredible recipe!!
Anita
Wow, I looking forward to making some of your recipes. They look very Delicious.
Kelly
How important is the mustard and the sparkling water? The only whey protein I have is French vanilla flavor. I think that would give The Onion rings a little flavor but not much with the paprika in the dry also. Will try these this weekend. ๐
Katrin Nรผrnberger
I'll be honest, I don't think vanilla flavour and onion rings would go together well. Vanilla whey may also be sweetened a little. If possible, I would see whether you can find unflavoured whey protein powder.
Molly
Can I use Bovine protein as I don't have Whey?
Katrin Nรผrnberger
I have not tried it. However, my feeling is that collagen peptides are going to give a more oily and sticky result.
Sarah in CA
These were fantastic. Since my daughter is dairy free I used egg white powder. Since no one knows that these are supposed to taste otherwise, they all loved them.
Brenda
Delicious and easy to make.
JanJan
Hi there, Could I use this method with coating chicken pieces, prawns and fish goujons??? The onion rings look delish and will be definately trying. Thank you for the recipe.
RachelH
Works great for fried chicken.
Marcelle Costanza
Just saw your section on the air fryer method. I think the oil frying is actually easier.