Simple Classic Creamy Mushroom Pastry Quiche

Preheat your oven to 450 degrees F (230 degrees C).

Lay out pie shell in a pie plate and bake in the preheated oven for 7 minutes. Carefully remove the shell from the oven and sprinkle cheese into the warm shell. Reduce oven temperature to 325 degrees F (165 degrees C).

Melt butter in a pan over medium-high heat. Sauté mushrooms and onion in hot butter until mushrooms give off their liquid and the onion is translucent, 5 to 7 minutes. Spoon the mushroom mixture over cheese in the pie shell.

Beat eggs in a bowl until smooth; add milk, cream, salt, and pepper and mix until equally incorporated. Pour this mixture over the mushroom mixture in the pie shell.

Bake in the oven until a knife inserted into the filling comes out clean, 35 to 40 minutes. Cool for 5 to 10 minutes before slicing.