This recipe for a Keto Blooming Onion is easy, delicious, and makes a great appetizer! Complete with a recipe for Horseradish dipping sauce. This ketofied version of the classic appetizer is a far cry nutritionally from their restaurant counterparts, but right on par in the flavor department.

Jump to:
- Preparation and cooking overview
- Chef's note
- 🧅 Ingredients for this keto blooming onion recipe
- Ingredient substitutions
- Additional ingredients
- Cooking tools required
- Tools substitute options
- How to make a gluten-free Baked Blooming Onion: step-by-step guide
- Cooking methods
- Preparation steps
- Cooking instructions
- What to serve with a keto-blooming onion?
- How to make it healthier
- Time-saving tips
- What can I prepare ahead of time?
- Storage and reheating instructions
- Storage tips
- Reheating best practices
- Recipe wrap-up and conclusion
- Frequently asked questions
- 📖 Recipe
Preparation and cooking overview
Preparing keto-blooming onion takes only 40 minutes. Cut the onions into petals, dip in beaten egg, coat with flour mixture, and drizzle with olive oil. Then, bake in the oven at 400°F (200°C) for 30 minutes until golden.
Chef's note
Get creative with your seasoning by adding a pinch of your favorite herbs or spices to the flour mixture – think garlic powder, fresh herbs, or even a touch of grated Parmesan for an extra layer of flavor. If you're looking to up the heat, amp up the cayenne pepper for a spicier kick.
🧅 Ingredients for this keto blooming onion recipe
Horseradish sauce
Ingredient substitutions
Don't fret if there's a particular ingredient you don't have. These handy substitutions are here to save the day:
Additional ingredients
Want to take this appetizer to a whole new level of deliciousness? Add these flavorful ingredients:
Cooking tools required
To make this keto-blooming onion recipe, you will need the following tools:
Tools substitute options
How to make a gluten-free Baked Blooming Onion: step-by-step guide
Cooking methods
Preparation steps
- Gather and measure all the required ingredients.
- Peel the onions.
- Crack the eggs into a small bowl.
Cooking instructions
- Preheat oven to 400°F (200°C). Whisk the eggs in a small bowl. In another small bowl, mix together the almond flour, coconut flour, paprika, salt, and cayenne. In another small bowl, combine all of the ingredients for the sauce and refrigerate until ready to use.
- To cut the onions, start by cutting off ½ inch of the pointy side of the onion, then peel off the outside layer. Lay the onion cut side down. Then, starting a ½ inch from the top (the end that’s not cut off), make 4 cuts through the onion across from each other. Repeat between the cuts until you have between 8-12 cuts, depending on the size of your onion. Flip the onion over and gently fluff out the petals.
- Dip each onion into the egg mixture, making sure to coat the inside and outside of each petal, let the excess fall off, then dredge through the flour mixture. You can use a spoon to make sure you get flour on each petal. Place the onions in a large 10.5″ cast iron skillet and drizzle or spray with about 1 tablespoon of olive oil.
- Cover the skillet with aluminum foil and transfer to the oven. Bake covered for 15 minutes. Remove the foil and bake for another 15 minutes. If the onions haven’t browned enough, you may place them under your broiler set to high for 5 minutes until golden brown. Serve with the horseradish sauce.
Make the horseradish sauce
- Take an 8 to 10" horseradish root, peel it, and chop it into pieces.
- Add the chopped pieces to a small food processor. Add a little water, vinegar, and a pinch of salt, and blend. Transfer the prepared horseradish to an airtight jar.
- In a small bowl, add 1½ tablespoons of the prepared horseradish and combine it with other sauce ingredients, including mayonnaise, ketchup, cayenne pepper, and paprika.
- Your keto horseradish sauce is ready.
Chef's pro tip
Choose an onion of about softball size. For a uniformly coated and crispy onion, give each petal a luxurious dip into the egg mixture and let the excess drip off before dredging it through the flour mixture. Additionally, use a spoon to sprinkle flour on each petal for full coverage. This technique prevents clumping and ensures a beautiful, golden crust on every petal.

What to serve with a keto-blooming onion?
The blooming onion is a versatile keto appetizer that effortlessly complements a wide range of foods. The following dishes pair well with this recipe:
How to make it healthier
Time-saving tips
What can I prepare ahead of time?
Storage and reheating instructions
Storage tips
Note: Freezing is not recommended for the keto-blooming onion, as the texture may become soggy upon thawing.
Reheating best practices
Recipe wrap-up and conclusion
And there you have it, a crispy, golden Keto Blooming Onion that's as delightful to look at as it is to savor. With each petal offering a burst of flavors and textures, this low-carb treat is perfect for sharing with friends at gatherings, as an appetizer to impress, or simply as a snack during your cozy movie nights.
With its enticing aroma and indulgent taste, this dish is ready to steal the show at any mealtime – be it lunch, dinner, or a satisfying snack. Don't just wait for special occasions; make any day extraordinary with this mouthwatering recipe.
Frequently asked questions
📖 Recipe

Keto Blooming Onion
Ingredients
- 3 medium onions
- 2 large eggs
- ½ cup almond flour
- ¼ cup coconut flour
- 1 tablespoon paprika
- ½ teaspoon salt
- ¼ teaspoon cayenne pepper
- 1 tablespoon olive oil
Horseradish Sauce:
- ¼ cup mayonnaise
- 1 tablespoon ketchup
- 1 ½ tablespoons prepared horseradish
- ¾ teaspoon cayenne pepper
- ½ teaspoon paprika
- Salt and pepper to taste
Instructions
- Preheat oven to 400° F. Whisk the eggs in a small bowl, in another small bowl mix together the almond flour, coconut flour, paprika, salt, and cayenne. In another small bowl combine all of the ingredients for the sauce, refrigerate until ready to use.
- To cut the onions, start by cutting off a ½ inch of the pointy side of the onion then peel off the outside layer. Lay the onion cut side down. Then, starting a ½ inch from the top (the end that’s not cut off), make 4 cuts through the onion across from each other. Repeat between the cuts until you have between 8-12 cuts depending on the size of your onion. Flip the onion over and gently fluff out the petals.
- Dip each onion into the egg mixture making sure to coat the inside and outside of each petal, let the excess fall off then dredge through the flour mixture, you can use a spoon to make sure you get flour on each petal. Place the onions in a large 10.5″ cast iron skillet and drizzle or spray with about 1 tablespoon of olive oil.
- Cover the skillet with aluminum foil and transfer to the oven. Bake covered for 15 minutes, remove foil and bake another 15 minutes. If the onions haven’t browned enough you may place them under your broiler set to high for 5 minutes until golden brown. Serve with the horseradish sauce.
Make the horseradish sauce
- Take an 8 to 10" horseradish root, peel it, and chop it into pieces.
- Add the chopped pieces to a small food processor. Add a little water, vinegar, and a pinch of salt, and blend. Transfer the prepared horseradish to an airtight jar.
- In a small bowl, add 1½ tablespoons of the prepared horseradish and combine it with other sauce ingredients, including mayonnaise, ketchup, cayenne pepper, paprika, and seasonings.
- Your keto horseradish sauce is ready.
Ginger Wroot says
Looks so yum! How many servings did you calculate for this recipe? --Ginger
Alex Lester says
Hi Ginger, the serving size can always be found at the top of the recipe card. it's super small font so it's easy to miss. This recipe, with the 3 onions, serves 6. So, it's 1/2 an onion per serving. Hope this helps!
Jamie Hunt says
Can you use just almond flour?
Darren Lovely says
Turned out pretty good, in the future I would use a jumbo white onion, I just used a regular yellow onion as that is all I had, did not make the dip as had something close enough in the fridge
Harris Sweet says
Can I use just coconut flakes instead of almunds?
Cast Iron Keto says
Hi Harris - well, I mean I guess you could make a coconut style blooming onion. We haven't tried it so we can't say that it will work but you could try using our breading that we use in our Keto Coconut Shrimp recipe as the breading for the onion. Let us know if you give it a go.
Marsha Whitt says
Would this bake up well if I completely cut the onion into petals and prepared the petals accordingly then baked in one layer? Would like to serve the petals at a tea party.
Cast Iron Keto says
They should work perfectly that way!