Preheat oil to 350 F in large Dutch oven or deep fryer.
Combine hot sauce, minced garlic, and butter in a large mixing bowl. Set aside.
Whisk together cornstarch, flour, baking powder, garlic powder, celery salt, and cayenne. Add cold water and vodka, then lightly whisk until a smooth, pancake-like batter forms. Use additional water, 1 tbs at a time, as needed.
Add 1/4 to 1/2 of the cauliflower to the batter and stir to coat. Working with one piece at a time, lift from batter and let excess drip back into the bowl, then transfer to the hot oil. Repeat until the fryer is full but not crowded.
Rotate and agitate the cauliflower in the fryer to prevent sticking and to ensure all sides crisp up. Cook until evenly golden brown, about 6 minutes.
Transfer to a paper towel lined plate to drain and season with salt if desired.
Once the cauliflower has all cooked and drained, transfer to the bowl with the hot sauce and toss to evenly coat.