In a mixing bowl combine eggs and milk. Stir in cheese, onions, and bacon. Place piecrust in a 9-inch pie plate.
Flute edges high.
Line crust with a layer of heavy-duty foil. Bake in a 450 degree oven for 5 minutes. Carefully remove foil from piecrust and bake about 5 minutes more or till piecrust is nearly done. Remove piecrust from the oven. Reduce the oven temperature to 325 degrees.