Step 1: Prepare the Onion
Cut off 1/2 inch from the top (pointy end) of the onion and peel off the papery skin, leaving the root end intact. Place the onion cut-side down on your cutting board. Starting about 1/2 inch from the root, make vertical cuts all the way down through the onion to the cutting board. Rotate and continue cutting to create 12-16 evenly spaced sections. Turn the onion over and gently separate the petals, being careful not to break them off.

Step 2: Soak the Onion
Place the cut onion in a large bowl of ice water and let it sit for 10-15 minutes. This helps the petals open up more and removes some of the onion’s sharpness. Remove and pat thoroughly dry with paper towels, getting between the petals as much as possible.

Step 3: Prepare the Coating Station
In a shallow bowl, mix together the seasoning blend. Add 1 1/2 cups flour to the seasoning mix and whisk to combine. Reserve the remaining 1/2 cup flour in a separate bowl. In another shallow bowl, whisk together eggs and milk until well combined.

Step 4: First Coating
Dust the onion all over with the reserved 1/2 cup plain flour, getting between all the petals. Turn upside down and tap to remove excess flour.

Step 5: Egg Wash
Dip the floured onion into the egg mixture, using your hands or a spoon to coat between all the petals thoroughly. Let excess egg drip off.

Step 6: Final Coating
Coat the onion generously with the seasoned flour mixture, again making sure to get between all the petals. Press the coating gently to adhere. Place on a baking sheet and let rest for 5-10 minutes.

Step 7: Heat the Oil
In your large pot or Dutch oven, heat oil to 350°F (use your thermometer to monitor). You need enough oil so the onion will be about 3/4 submerged.

Step 8: Fry the Onion
Carefully place the onion in the hot oil root-side up. Fry for 3 minutes, then carefully flip using tongs or a spider strainer. Fry for another 3-4 minutes until deep golden brown all over. The total frying time is about 6-8 minutes.

Step 9: Drain
Carefully remove the onion and place it on a paper towel-lined baking sheet or plate. Let drain for 1-2 minutes.

Step 10: Make the Sauce
While the onion cools slightly, whisk together all dipping sauce ingredients in a small bowl. Adjust seasoning to taste.

Step 11: Serve
Transfer the blooming onion to a serving platter, place the dipping sauce in the center or alongside, and serve immediately while hot and crispy.