In a large skillet, heat 1 tbsp of avocado oil over medium heat. Add panko breadcrumbs to hot oil and toast for 3-4 minutes, stirring constantly. Once the crumbs look golden, quickly remove them from the heat and transfer to a plate to cool completely. Set aside.
Preheat oven to 425 degrees and line a baking sheet with parchment paper.
In a large bowl, beat egg, whisk in flour, 1 tbsp mayonnaise, 2 tsp Sriracha, ½ tsp salt, 1 tsp garlic powder and buttermilk.
Add cauliflower florets to bowl and toss with a spatula or spoon until everything is thoroughly coated, making sure to get the marinade into all the nooks and crannies.
Dredge the coated cauliflower florets in the cooled panko breadcrumbs, pressing gently to make sure crumbs adhere to all sides.
Place breaded cauliflower, evenly spaced, apart onto parchment lined baking sheet. Bake for 18-22 minutes until cauliflower is cooked through.
While the cauliflower is in the oven, make the Bang Bang sauce. In a small bowl, stir together ¼ cup mayonnaise, sweet chili sauce, ½ tsp garlic powder, 2 tsp Sriracha and juice of half a lime.
When the cauliflower comes out of the oven, serve immediately with Bang Bang sauce drizzled over the top or on the side for dipping.