Preheat the oven to 400°F and line a baking sheet with parchment paper.
Cut the cauliflower into bite-sized florets and place them in a large bowl.
In a separate bowl, whisk together the cornstarch, garlic powder, onion powder, paprika, and salt. Add the milk to the dry ingredients and whisk until a smooth batter forms.
Pour the batter over the cauliflower and toss until all florets are evenly coated. Spread the coated cauliflower evenly on the baking sheet in a single layer.
Bake for 30 minutes, flipping halfway through, until golden and crisp.
While the cauliflower bakes, melt the butter and stir it into the hot sauce to make the buffalo sauce.
When the cauliflower is done, transfer to a large bowl and toss gently with the buffalo sauce until fully coated.
Serve immediately with ranch or blue cheese dressing.