1 large Maui or sweet onion
2 cups Flour
1/3 cup Potato starch
1/ 3 cupCorn starch
1 1/2 tsp Baking powder
4 tsp kosher Salt
2 cups buttermilk
Canola oil for frying
1/2 cup Mayo
1 tbs horseradish
1 tbsp ketchup
1/3 tsp paprika
1/3 tsp cayenne
1/4 tsp kosher salt
Cut the onion: Cut the top off of the onion and peel the outer layer. Starting 1/3 inch from the root make a downward cut all the way down. Make quarter inch cuts around the onion. Turn the onion over and use your fingers to gently open up the layers. Remove the middle core of the onion. Submerge and soak the onion in buttermilk for 10 minutes.
Make the dredge: Mix all the dry ingredients together in a large bowl.
Make sure your onion has buttermilk all over the layers and coat it in your dredge. You want to make sure you pull back all the layers gently and get the dredge in all the nook and crannies. Shake off any excess. Let it sit for 5-10 minutes.
In a deep pot add 4 to 5 inches of canola oil depending on how big your onion is. Heat your oil to 350 degrees Fahrenheit.
Gently drop in your onion top side down. Fry until golden brown, it should take about 9-11 minutes for large onions 5-6 minutes for small onions. Flipping it halfway through.
Sprinkle with Cayenne, paprika, and garlic powder.
Add all the ingredients to a bowl and mix throughly.
Chill in the fridge before serving.