Preheat the oven to 425 degrees Fahrenheit with a rack in the lower third of the oven. Line a large, rimmed baking sheet with parchment paper to prevent the cauliflower from sticking.
Cut the cauliflower into large florets, about 2 to 3 inches in size. In a medium mixing bowl, toss the cauliflower with the cornstarch, garlic powder and pepper. Then drizzle in the olive oil and toss until lightly and evenly coated.
Arrange the florets evenly across the prepared baking sheet. Set the used bowl aside, but keep it nearby.
Roast the cauliflower for 20 minutes on the lower rack, then gently toss. Return the pan to the lower rack and bake until the cauliflower is tender and golden, about 10 more minutes.
Meanwhile, in your reserved bowl, combine the hot sauce and melted butter. Whisk to combine. Taste, and stir in another tablespoon of hot sauce if desired (it won’t taste as intense once it’s on the cauliflower). Once the cauliflower is golden, transfer it to the bowl and gently toss until the cauliflower is well coated.
Arrange the cauliflower on the pan in a single layer once again. Return the pan to the oven and bake until the cauliflower is blistered in spots, about 10 more minutes. Serve as desired.
MAKE IT DAIRY FREE/VEGAN: Substitute vegan butter, such as Miyoko’s Creamery brand. Serve with a suitable dip, if desired—this Creamy Avocado Dip might be nice.