Preheat oven to 450℉. In a small saucepan, heat hot sauce and butter until butter is melted and sauce is bubbling.
On a large baking sheet, toss cauliflower with ¾ cup hot sauce mixture and spread out in 1 layer making sure there is space between florets. Roast until browned, 25-30 minutes.
In a large bowl, mash together avocado, lime juice, garlic, and salt.
Sprinkle cauliflower with green onion and cilantro. Serve avocado and remaining hot sauce-butter mixture on the side.