Slice sweet onions into bite-sized wedges and soak in buttermilk for about 10 minutes.

In a shallow dish, combine flour, paprika, garlic powder, onion powder, cayenne pepper, and salt.

Coat the soaked onion wedges in the flour mixture, dip in buttermilk, and roll in panko breadcrumbs.

Heat vegetable oil in a large skillet to 350°F (175°C).

Fry the coated onion wedges in small batches for 2-3 minutes until golden brown.

In a mixing bowl, combine mayonnaise, ketchup, Worcestershire sauce, and horseradish for dipping sauce.

Serve the fried blooming onions with the dipping sauce on a decorative platter.