Line a 10-inch pie plate with pastry and bake five minutes at 450 F. Cook bacon until crisp and remove it from the skillet. Pour off all off all but one tablespoon of the fat remaining in the skillet. Cook the onion in the remaining fat until the onion is transparent. Crumble the bacon and sprinkle the bacon, onion and cheeses over the inside of the partly baked pastry. Combine the eggs, cream, nutmeg, salt and pepper and strain over the onion-cheese mixture. Bake fifteen minutes at 450 F. Reduce the oven temperature to moderate, 350 F., and bake until a knife inserted on inch from the pastry edge comes out clean, about 10 minutes longer.
