Combine all ingredients for Dipping Sauce in a bowl, stir, and set aside.
Cut the top inch off the Onion, leaving the root in tact. Peel of the skin, and place the onion cut side down on a cutting board. Starting 3/4 inch from the root, slice down all the way. Rotate 90 degrees, and repeat three times so that there are four even cuts.
Continue slicing between each petal of onion, until 16 cuts have been made. Flip the onion right side up, and gently pry open the petals of the onion so that they are exposed.
Whisk together Egg and Milk in a bowl. Whisk together dry ingredients in a separate bowl.
Place onion in flour mixture, and cover completely, ensuring every petal is dusted in flour. Tap off excess flour, and submerge into Egg Mixture covering completely. Remove from Egg Mixture and place in Flour Mixture one more time, ensuring all sides of the onion are evenly coated.
Heat oil in a large pot to 400 degrees Fahrenheit. Using a spider/slotted spoon, gently lower breaded onion into oil, petal side down. Fry for seven to eight minutes or until golden and crispy. Drain on paper towel.
Serve hot with Dipping Sauce on the side. Enjoy! :)