Preheat oven to 425° and line a large sheet pan with parchment paper.
Toss the cauliflower florets with the avocado oil, cornstarch, garlic powder, and onion powder in a large bowl (save this bowl for step 5).
Spread the cauliflower evenly across the prepared baking sheet and bake in the preheated oven for 30 minutes or until golden brown, tossing halfway through to cook evenly.
Meanwhile, stir together the buffalo sauce and melted butter.
Once the cauliflower is golden, carefully transfer it to the large bowl and toss with the hot sauce mixture until well coated.
Spread the buffalo cauliflower back onto the baking sheet evenly and bake an additional 10 minutes. Serve with Greek yogurt ranch dressing!