Preheat oven to 350 degrees.
If using a prepared pie crust, let it rest outside of the refrigerator for ~15 minutes.
Mix egg whites, milk, chopped spinach, shredded cheese, chopped sundried tomatoes, salt and pepper in a bowl. All quiche mixture into a prepared pie plate or tart pan with pie crust dough.
Bake for 45 minutes. Let the quiche cool for 10 minutes before serving.