How to Make It
Preheat oven to 400°. Fit piecrust into a 9-inch tart pan lightly coated with cooking spray. Bake crust 8 to 10 minutes or until lightly browned. Cool.
Cook bacon in a large skillet over medium-high heat, stirring occasionally until crisp; remove bacon, and drain on paper towels. Reserve drippings in skillet.
Reduce heat to medium, and melt butter with drippings; add onions and a pinch of salt. Cook, stirring often, 5 minutes. Cover and cook about 10 more minutes or until onions are soft and lightly browned. Uncover and cook, stirring often, 2 to 3 minutes or until liquid evaporates. Remove skillet from heat, and cool completely.
Whisk together crème fraîche and next 6 ingredients in a medium bowl. Stir in bacon and onions. Spread mixture in prepared crust.
Bake at 400° for 25 to 30 minutes or until golden and set. Cool on a wire rack 10 minutes before slicing.
Vegetarian Creamed Onion Tart: Omit bacon. Prepare recipe as directed, substituting 1 Tbsp. extra virgin olive oil for bacon drippings.
Hands-on 35 min.; Total 1 hour, 45 min.