Prepare the pie crust: If using a store-bought crust, thaw it according to package instructions. If making your own crust, follow the recipe in your favorite cookbook or online. Once the dough is ready, roll it out on a floured surface to a 12-inch circle. Place the dough in a 9-inch pie dish and press it into the bottom and sides. Trim off any excess dough.
Chill the pie crust: Wrap the pie dish in plastic wrap and refrigerate for at least 30 minutes, or up to 5 days.
Preheat the oven to 375°F (190°C).
Partially blind-bake the pie crust: Line the chilled pie crust with parchment paper and fill with pie weights or dried beans. Bake for 15-16 minutes, or until the edges of the crust are starting to brown. Remove the pie crust from the oven and carefully lift out the parchment paper and weights. Prick the bottom crust with a fork.
Reduce the oven temperature to 350°F (177°C).
Whisk together the filling ingredients: In a large bowl, whisk together the eggs, milk, cream, salt, pepper, and your chosen add-ins.
Pour the filling into the pie crust and bake for 45-55 minutes, or until the center is just about set. Don't over-bake! You can use a pie crust shield to prevent the edges from over-browning.
Let the quiche cool for 15 minutes before slicing and serving. You can also cool it completely before serving.