Baking this quiche-style tart in a jelly-roll pan makes it easy to cut and serve. A flaky, buttery crust sets off the earthy flavor of the mushrooms. The tart is equally good served warm or at room temperature.

CRUST
3 cups all-purpose flour
1/2 teaspoon salt
1 cup plus 1 tablespoon unsalted butter, chilled, cut up
1 egg
6 to 7 tablespoons ice water

FILLING
2 tablespoons butter
2 large leeks, white and light green parts, thinly sliced
1 lb. assorted mushrooms (shiitake, cremini, oyster), thinly sliced (discard shiitake stems)
1 1/4 teaspoons salt, divided
1/2 teaspoon freshly ground pepper, divided
1 medium tomato, chopped
2 tablespoons chopped fresh tarragon
5 eggs
1 cup heavy whipping cream

1. Place flour and 1/2 teaspoon salt in food processor; pulse to combine. Add 1 cup plus 1 tablespoon butter; pulse until mixture resembles coarse crumbs with some pea-sized pieces. In small bowl, whisk together egg and 6 tablespoons of the water. Add egg mixture to food processor; pulse until dough just begins to form, adding additional 1 tablespoon water if dough is dry. (Dough also can be made by hand using pastry blender.) Turn out onto lightly floured surface; shape into flat round. Cover and refrigerate at least 1 hour or up to 3 days.

2. Heat oven to 400°F. On lightly floured surface, roll dough into 17x12-inch rectangle 3/8 inch thick. Fold dough in half to transfer; line 15x10x1-inch pan with dough. Trim edges, leaving 1/2-inch overhang. Turn overhang under, even with edge. Prick bottom of crust all over with fork. Line crust with foil; fill with pie weights or dry beans.

3. Bake 12 minutes. Remove foil and weights; bake an additional 10 to 12 minutes or until light golden brown. Remove from oven; reduce oven temperature to 325°F.

4. Meanwhile, to make filling, heat 2 tablespoons butter in large skillet over medium heat. Add leeks; cook 4 to 5 minutes or until limp. Add mushrooms, 3/4 teaspoon of the salt and 1/4 teaspoon of the pepper; cook, stirring frequently, 6 to 8 minutes or until tender. Add tomato; cook 3 to 5 minutes or until mushroom juices have nearly evaporated. Remove from heat; stir in tarragon. (Filling can be made up to 1 day ahead. Cover and refrigerate.)

5. In medium bowl, whisk together eggs, cream, remaining 1/2 teaspoon salt and 1/4 teaspoon pepper. Spread mushroom mixture over crust; top with egg mixture. Bake 30 minutes or until custard has set and puffed. Cool on wire rack 10 minutes. Cut into 30 (2-inch) squares. Place on platter; serve warm or at room temperature.

36 pieces

PER PIECE: 135 calories, 9.5 g total fat (5.5 g saturated fat), 3 g protein, 9.5 g carbohydrate, 60 mg cholesterol, 130 mg sodium, .5 g fiber