Step 1

Preheat oven to 350 degrees F (175 degrees C).

Step 2

Grease a 10-inch pie dish.

Step 3

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.

Step 4

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.

Step 5

Stir mushrooms, spinach, and Cheddar cheese into egg mixture. Pour into prepared pie dish.

Step 6

Bake in the preheated oven until lightly browned and a toothpick inserted into the middle of the quiche comes out clean, about 45 minutes.