CARAMELIZED LEEK QUICHE

Steps:

• On a lightly floured surface, roll out dough to a 12-inch circle. Fit dough into a 10-inch round fluted tart pan with a removable bottom, pressing into edges. Trim dough to a 1/2-inch overhang all around. Fold edge of dough over to create an edge that extends 1/4-inch above the pan. Lightly prick bottom of dough all over with a fork. Chill until firm about 30 minutes.
• Preheat oven to 375 degrees. Line bottom of dough with parchment paper, leaving at least a 1-inch overhang. Fill with pie weights or dried beans. Bake until the edges are just beginning to turn golden, about 30 minutes. Remove parchment paper and weights; continue baking until lightly golden all over, 10 to 15 minutes more. Cool tart shell completely on a wire rack.
• Heat olive oil in a medium skillet over medium heat. Add leeks and thyme and cook, stirring occasionally, until leeks soften and begin to brown, 10 to 15 minutes. Season with salt and pepper.
• Sprinkle half of the cheese over the bottom of the tart shell, top with cooked leek mixture and sprinkle with remaining cheese. In a medium bowl, whisk together eggs, yolk, milk, cream, and a pinch of salt and pepper. Pour mixture over leeks and cheese. Bake until puffed and golden brown, 30 to 35 minutes. Transfer to a wire rack to cool 10 minutes before serving, or serve at room temperature.