Heat the oven. Preheat to 425°F (220°C).
Line a large baking sheet with parchment for easy cleanup.
Prep the cauliflower. Cut into medium florets. Aim for similar sizes so they roast evenly. Pat dry to help them crisp up.
Season and oil. In a bowl, toss cauliflower with olive oil, garlic powder, onion powder, smoked paprika, salt, and pepper.
Spread in a single layer on the baking sheet.
Roast until golden. Bake for 20–25 minutes, flipping halfway. You want browned edges and tender stems. If using an air fryer, cook at 400°F (205°C) for 14–16 minutes, shaking once.
Make the buffalo coating. Stir together buffalo sauce and melted vegan butter.
This adds richness and helps the sauce cling to the cauliflower.
Toss and finish. Transfer hot roasted cauliflower to a bowl, pour the buffalo mixture over, and toss to coat. Return to the baking sheet and roast 5 more minutes to set the sauce.
Mix the slaw. In another bowl, combine cabbage, carrot, and green onions. Stir together vegan mayo, apple cider vinegar, maple syrup, and celery salt.
Toss with the vegetables until lightly coated. Taste and adjust salt or vinegar.
Warm the tortillas. Heat in a dry skillet, over a gas flame, or wrapped in foil in the oven for a few minutes. Warm tortillas are more flexible and taste better.
Assemble the tacos. Add a layer of slaw to each tortilla.
Top with buffalo cauliflower, avocado slices, and cilantro. Squeeze lime over the top.
Serve right away. These are best hot and crispy, with extra buffalo sauce on the side if you like more heat.