Make and blind bake the crust in a 10-inch pie dish. Use the instructions in the link for my Buttery Flakey Pie Crust under Ingredients. Use the instructions for partially blind baking the crust.
Reduce the oven temperature to 350˚F (177˚C) and place the oven rack in the middle of the oven.
Sauté the veggies you plan to use in the quiche. Set aside to cool.
Grate the cheese(s). Set aside.
Using a handheld mixer fitted with a whisk attachment and a large bowl, beat together the eggs, heavy cream, whole milk, salt, and pepper until foamy and completely combined.
Fold the cooled vegetables and cheese(s) into the egg mixture using a silicone spatula and pour the entire contents into the blind baked crust. I always recommend placing the quiche dish on a sheet pan when baking, just in case the filling runs over the rim of the pie dish while the quiche bakes. Bake the quiche until the center is just about set, about 45-55 minutes at sea level and approximately 65 minutes at high altitude (>5000 ft.) Be careful not to over-bake the quiche and cover with foil if the crust edges brown more than you wish.
Cool the baked quiche on a wire rack or other cooling rack for 10-15 minutes to allow the eggs to set before slicing into pieces. Serve warm or at room temperature.