Prep the Onions:

Peel and trim the ends off each onion.

Cut each onion into quarters or sixths—keeping the root end just barely intact if possible.

Soak in ice water for 30 minutes to help them bloom slightly and soften. Drain and pat dry.

Mix the Coating:

In one bowl, whisk together flour, cornstarch, and all spices.

In a second bowl, mix buttermilk and egg.

Bread the Onion Bites:

Dip each onion piece in the flour mixture, then the buttermilk mixture, then back into the flour mixture. Press gently so the coating sticks.

Fry or Air-Fry:

Frying:

Heat oil in a deep pan to 350°F (175°C).

Fry onions in small batches for 2–3 minutes, or until golden brown and crispy. Drain on paper towels.

Air-Frying:

Preheat air fryer to 375°F (190°C).

Spray breaded onions with oil and air fry for 8–10 minutes, flipping halfway through.

Make the Sauce:

In a small bowl, stir together mayo, ketchup, horseradish, paprika, garlic powder, and a pinch of salt and pepper. Chill until ready to serve.

Serve & Enjoy:

Serve the crispy blooming onion bites with the dipping sauce on the side. Best eaten warm!