Rustic Sweet Onion Tart

1 refrigerated piecrust (7.5 ounces) (see note)2 medium sweet red onions (see note)6 ounces Swiss-cheese slices3 large eggs2 teaspoons all-purpose flour#190; cup half-and-half#188; teaspoon salt#8539; teaspoon black pepperHeat the oven to 350 degrees.Place the piecrust in a 12-inch tart pan with a removable bottom. Press the dough along the ridged sides. Set aside.Peel and slice the onions into 1/4-inch rings. Sprinkle half the onions over the bottom of the crust. Top with half the cheese. (Cheese will not cover the onions; this is fine.) In a medium bowl, mix together eggs, flour, half-and-half, salt and black pepper. Mix well until frothy. Pour half the egg mixture over the cheese. Layer the remaining onion, cheese and finally egg mixture. Bake uncovered for 50 minutes, until golden brown. Remove from the oven, and let cool 5 minutes. Lift from the sides (see note), and serve.Serves six.Cook's note: One piecrust is half of a 15-ounce box. If you can't find sweet red onions, sweet white will work fine. Here's a trick for removing the tart from the outside ring of the pan: Place the bottom of the pan over a small bowl. The pan ring will fall away (if sides have shrunk enough) or you can gently pull down on the pan ring to remove.@Recipe nutrition:Nutrition values per serving: 289.5 calories, 9 g fat (2 g saturated), 26.5 g carbohydrates, 3.5 g fiber, 27 g protein, 75 mg cholesterol, 844 mg sodium.