Blind bake your pie crust for 15 minutes at 375°, until it is lightly browned.
Fillings like bacon, ham, mushrooms, and onions should be pre-cooked. You can just toss them in a pan and cook them while your pie crust is blind baking. This way, they will be ready to go when you are mixing your quiche.
With a whisk or mixer with whisk attachment, beat the eggs, heavy cream, milk, salt, pepper.
Add fillings and cheese to the egg and milk mixture.
Pour quiche mixture into your partially baked pie crust and cook at 350° for 45-60 minutes. I gave a range of cooktime because it will often depend on your oven and how many fillings you added. If your pie crust starts to brown too much, you can use a pie crust shield or aluminum foil to cover it and prevent it from browning too much. You want to cook it until the quiche is set (if you give it a shake in the oven, you will see it is set). It may start to lightly brown on top - that's okay!
Let the quiche cool for at least 20 minutes. Serve and enjoy!