Preheat oven: Preheat to 450°F (232°C) and prepare a wire-rack lined baking sheet.
Make batter: In a large bowl, whisk together flour, baking powder, garlic powder, smoked paprika, and salt. Gradually whisk in milk until you have a thick, smooth batter. Stir in oil.
Coat cauliflower: Toss the cauliflower florets in the batter until evenly coated. Shake off excess and place on the wire rack in a single layer.
Bake: Bake for 20–25 minutes until the batter sets and edges begin to brown. Flip florets gently and bake another 10–15 minutes until crisp and golden.
Prepare buffalo sauce: While baking, combine hot sauce, melted butter (or vegan butter), and apple cider vinegar in a small saucepan over low heat. Stir until glossy and warm.
Sauce the wings: Remove cauliflower from oven and toss in the warm buffalo sauce to coat thoroughly.
Finish baking: Return sauced cauliflower to the rack and bake 4–6 more minutes to help sauce adhere.
Serve: Transfer to a platter and serve hot with ranch or blue cheese, celery, carrots, and lemon wedges.