Preheat oven to 450° F.  Carefully line a 9-inch tart or pie pan with unbaked pastry.  Do not trim.  Prick the bottom several times with the tines of a fork.  Line with a coffee filter; spread about a cup of dried beans or pie weights on coffee filter.  Bake for 10 to 12 minutes, or until lightly browned.  Let cool completely.  Remove coffee filter and beans.  While still in the pan, carefully trim away the excess crust with a serrated knife.  Set aside.

Whisk together 3 eggs and ¾ cup of milk.  Set aside.

Over medium heat, melt 1 Tablespoon of butter in a frying pan.  Add chopped onions; sauté for 10 to 15 minutes, or until lightly browned.  Remove from heat; set aside.

Crumble sausage in a frying pan.  Cook over medium heat until the sausage is thoroughly cooked and well crumbled.  Drain well on paper towels.  Set aside.

Preheat the oven to 375° F.

To assemble the quiche, begin by placing the crust on a baking sheet lined with non-stick aluminum foil.  Sprinkle sautéed onions evenly over the bottom of the crust, followed by the sausage, and then the shredded cheese.  Add the egg/milk mixture.  Bake at 375° F for 35 minutes, or until the mixture is set and the top is golden brown.  Let cool for 5 minutes before serving.  Yield:  6 servings.