Preheat an oven, then line a rimmed baking sheet with parchment paper. In a large bowl, whisk together buttermilk, flour, and hot sauce. Add the cauliflower florets, then gently toss to coat.
In a second bowl, combine breadcrumbs, garlic powder, and onion salt, then mix well. Place cauliflower in the breadcrumb mixture. Transfer each piece of cauliflower to the prepared baking sheet.
Cook until the florets are golden brown. While the cauliflower is cooking, make the sauce.
Combine unsalted butter, honey, cayenne pepper, garlic powder, sweet paprika, chili powder, Kosher salt, and black pepper in a saucepan. Heat over medium-high heat until the butter has melted and the spices become fragrant, stirring well.
Pour the hot honey sauce on top of the cauliflower, then toss well until evenly coated. Transfer to a large serving platter, then garnish with chopped parsley. Serve immediately with a Ranch or Blue Cheese dressing.