Blooming Onion Recipe by Sloane Layton from The Pioneer Woman.

Ingredients

Onion:

• 1 large yellow onion
• 2 cups buttermilk
• 1 1/2 cups all-purpose flour
• 2 tsp kosher salt, plus more for sprinkling
• 3/4 tsp baking powder
• 3/4 tsp black pepper
• 1/2 tsp cayenne pepper
• Canola oil, for frying

Dipping sauce:

• 1/4 cup mayonnaise 
• 1 Tbsp ketchup
• 1/2 Tbsp prepared horseradish 
• 1/4 tsp paprika
• 1/4 tsp kosher salt
• 1/8 tsp black pepper
• 1/8 tsp dried oregano leaves
• Pinch of cayenne pepper

Directions

1. Prepare the onion: Cut ½ inch off the top and peel the outer layer. Trim the dried root but keep the base intact. Slice the onion from top to bottom, about 16 cuts, stopping before the root. Separate the petals gently with your fingers and soak the onion in buttermilk for at least 1 hour or overnight.
2. Make the dipping sauce: Mix mayonnaise, ketchup, horseradish, paprika, salt, pepper, oregano, and cayenne. Cover and refrigerate.
3. Prepare the flour mixture: In a bowl, whisk flour, salt, baking powder, pepper, and cayenne.
4. Fry the onion: Heat oil to 375°F in a large pot. Remove the onion from the buttermilk, let it drip, and coat it with the flour mixture, making sure all the petals are covered.
5. Fry and serve: Fry the onion, cut-side down for 3-4 minutes, flip, and fry for another 2-3 minutes until golden and crispy. Drain on paper towels, sprinkle with salt, and serve with dipping sauce.