Preheat the oven to 375. Unroll the pie crust and place it in a 9-inch pie plate that's no more than an inch thick. Trim or flute the edges.
Lay a sheet of aluminum foil over the surface of the crust and fill the crust with something to weigh it down: dry rice, dry beans or pie weights work great. Place the crust in the oven to blind bake just until the crust dries out and firms slightly. About 12 minutes.
Remove the crust from the oven, lift the foil and weights out of the crust and set aside while you make the filling.
In a large skillet, cook the bacon over medium heat until crisp. Set the bacon aside and drain away all but 1 tablespoon of the bacon drippings from the skillet.
Add the onions to the fat in the skillet and cook until just translucent and softened. About 7 to 8 minutes. Turn off the heat and leave the onions in the skillet.
To the warm pie shell, add the bacon in an even layer. Spread over the onions evenly. Sprinkle on the cheese.
In a large measuring cup, beat together the eggs and the cream until smooth.
Carry your pie shell over to your oven and set the pie plate on your oven rack before adding the eggs. (Just to prevent spills.) Pour in the eggs within a 1/2 inch of the top of the crust.
Bake until a knife inserted an inch from the edge comes out clean and the center just jiggles--about 30 minutes. Yours may need longer if you use a deep dish pie plate so check the center and bake in 5 minute increments until the desired level of doneness is achieved.