Drain spinach well, pressing between layers of paper towels.
Whisk together eggs and next 3 ingredients. Stir in spinach, bacon, and cheeses. Pour mixture into frozen pastry shell; place on a baking sheet.
Bake at 375° for 40 to 45 minutes.
* 1/2 (15-ounce) package refrigerated piecrusts may be substituted. Prepare according to package directions.