Add salted butter, garlic, mushrooms, and green onions to the skillet and cook until the mushrooms start to become tender (~3 minutes)
Add the riced cauliflower to the skillet and continue to cook until the riced cauliflower is almost tender (~3 minutes)
Add remaining ingredients and stir until the parmesan cheese is well incorporated. Lower the heat so that the rice does not stick and cook until the cauliflower rice reaches your desired level of tenderness. Turn off the heat.