Melt butter in a skillet over medium heat; cook and stir sliced mushrooms until tender, about 5 minutes. Drain excess liquid, if necessary; set mushrooms aside.
Place sour cream, eggs, Parmesan cheese, flour, cream, onion powder, garlic powder, salt, and hot pepper sauce in a blender; blend until smooth, 30 seconds to 1 minute. Pour egg mixture into a large bowl.
Stir mushrooms, spinach, and Cheddar cheese into egg mixture. Pour into prepared pie dish.
Bake in the preheated oven until lightly browned and a toothpick inserted into the middle of the quiche comes out clean, about 45 minutes.
