Peel the onion and cut off the top, leaving the root intact. Place the onion root-side down. Carefully slice downward into sections without cutting through the root. Continue making cuts around the onion until it begins opening like flower petals naturally.

Gently spread the onion petals apart using your fingers. Be careful not to break them. The onion should look like a blooming flower. This step helps the coating reach every layer and creates the famous blooming onion appearance after frying.

In a large bowl, combine flour, paprika, garlic powder, onion powder, cayenne pepper, salt and black pepper. Stir until evenly mixed. These spices create the crispy flavorful coating that gives the onion its restaurant-style taste and golden crunchy texture.

In another bowl, whisk eggs and milk together until smooth. This mixture helps the flour coating stick properly to the onion. A smooth wet mixture creates an even crunchy crust that stays crispy after frying and holds seasoning beautifully.

Dip the onion into the flour mixture carefully. Spread flour between the petals for full coverage. Next, dip the onion into the egg mixture. Then coat again with seasoned flour. Double coating creates extra crunch and helps every petal fry perfectly golden.

Pour oil into a deep pan or pot and heat to 375°F or 190°C. The oil should be hot enough for quick crispiness but not smoking. Proper oil temperature prevents greasy coating and helps create crunchy onion petals with beautiful golden color.

Carefully place the onion into the hot oil using tongs or a slotted spoon. Fry for about 8 to 10 minutes until golden brown and crispy. Turn gently if needed for even cooking. Remove carefully and place onto paper towels to drain excess oil.

In a small bowl, combine mayonnaise, ketchup, horseradish, paprika, garlic powder, salt and black pepper. Stir until smooth and creamy. The sauce tastes slightly spicy and creamy. It perfectly balances the crunchy onion and adds extra flavor with every bite.

Place the blooming onion onto a serving plate carefully. Put the dipping sauce in the center or beside the onion. Serve immediately while crispy and hot. The crunchy petals taste best fresh from the fryer with creamy dipping sauce nearby.