Crust: 3 c. all-purpose flour 1 egg 1 egg yolk 1/8 tsp. kosher salt 1 c. (1/2-lb.) chilled butter, cut into small cubes 1 Tbsp. cold water
Filling: 4-lbs. Vidalia onions, cut into thin strips 4 Tbsp. butter 4 eggs 2 egg yolks 1/2 c. heavy cream or half-and-half 3 c. (12-oz.) Wisconsin Cheddar Cheese, shredded 16 slices bacon, diced, fried until crisp 1/3 c. fresh chives, chopped Salt and pepper Prepare dough by pulsing flour, 1 egg, 1 egg yolk and salt in a food processor. Add butter, piece by piece, pulsing until all is incorporated. Add water and pulse only until dough forms a ball. Remove; cover with plastic wrap and refrigerate at least 2 hours. Remove dough from refrigerator 30 minutes before assembling tarts. Meanwhile, prepare filling by cooking onions in butter in 2 large skillets until tender and translucent. Cool in a medium bowl. Beat 4 eggs, 2 egg yolks and cream together. Stir into onions; add cheese, bacon, chives and salt and pepper to taste. Preheat oven to 350° F. Divide dough in half. Roll each portion to fit in 10-inch tart pan with removable rim. Trim dough to fit rim height and prick bottom of dough with fork. Bake crust 7 minutes or just until it begins to turn golden brown. Remove from oven, add filling and bake 15 to 20 minutes more until egg mixture is set. Let cool 5 minutes before removing rim from tart pans. Cut into wedges.