If you're adding crispy turkey bacon, then, cook one strip of bacon into a frying pan until brown and crispy. Cut the bacon strip into small dice, set aside.
Preheat the oven to 425ºF. Line a baking sheet pan with parchment paper. Add the cauliflower florets into a prepared pan. Drizzle with oil, season with salt and pepper, toss to coat well. Spread the cauliflower for even baking. Roast for 20-30 minutes or until fork tender. Set aside.
In a 9" baking dish, combine cream, sriracha, egg, panko breading, turkey bacon, cheeses, garlic powder, mix to combine well.
Add the roasted cauliflower florets, stir to combine. Sprinkle more Parmesan cheese and mozarrella on top. Bake in 400ºF oven for 20-30 minutes or until golden brown and the cheeses are all melted.
After baking, while the casserole still hot, sprinkle crispy bacon and green onions on top. Serve warm