Preheat the oven to 450°F and line two large baking sheets with parchment paper.
In a large bowl, whisk together the flour, cornstarch, garlic powder, onion powder, paprika, and salt.
Add water to the dry ingredients and whisk until smooth.
Add cauliflower florets and stir to fully coat them with the batter.
Lift each floret from the batter, letting excess drip off, then arrange in a single layer on prepared baking sheets.
Bake for 10 minutes, then carefully flip the florets and swap the baking sheets on the oven racks.
Bake for another 10 minutes.
Remove from oven and brush with buffalo sauce.
Return to oven and bake for an additional 12 to 15 minutes until edges are dark and crisp.
Remove from oven and brush with more buffalo sauce before serving.
Serve with ranch, vegan ranch, or blue cheese dressing, if desired.