Mushroom Bacon Tart

Line baking pan with foil, leaving a 1-inch overhang on short sides. Unroll pastry and overlap rounds by 4 inches on a lightly floured working surface. Brush overlap area of bottom pastry round lightly with water, then press overlapping areas together.

Roll out pastry to form a rough rectangle (about 19- by 13-inches), then cut to a 15- by 12-inch rectangle (about 1/8 inch thick). Fit pastry into pan, trimming edges to leave about 3/4-inch-high sides. Lightly prick bottom and sides all over with a fork and chill until firm, about 30 minutes.

Preheat oven to 400F with rack in middle.

Meanwhile, pour 1 1/2 cups boiling water over dried mushrooms and soak until softened, 25 to 30 minutes.

Line pastry shell with foil and fill with pie weights or 2 cups dried beans. Bake until sides are set and edges are pale golden, 8 to 9 minutes. Remove foil and weights carefully and bake until bottom is light golden, 4 to 5 minutes. Cool pastry shell in pan on a rack.

Drain mushrooms in a fine-mesh sieve set over a bowl, squeezing mushrooms, and reserve liquid. Rinse mushrooms to remove any grit, then squeeze out excess water and chop.

Preheat oven to 325F with rack in middle.

Cook bacon in a 10-inch heavy skillet over medium heat, stirring, until crisp, then transfer to paper towels. Pour off all but 3 tablespoons fat from skillet, then cook fresh mushrooms and onion with a large pinch of salt over medium high heat, stirring occasionally, until mushrooms begin to brown, 4 to 6 minutes. (Use vegetable oil if not enough fat in skillet.) Stir in garlic, then add dried mushrooms with soaking liquid and briskly simmer, stirring occasionally, until liquid is totally evaporated, 6 to 8 minutes. Stir in bacon and scatter evenly over crust.

Whisk together eggs, cream, sage, and 1/2 teaspoon each salt and pepper, then pour over bacon mixture. Bake until custard is just set, 25 to 30 minutes. Cool tart in pan on a rack 30 minutes. Carefully lift out of pan using foil as an aid, then cut into 50 pieces (each about 1 1/2- by 1 1/4-inch). Serve warm or at room temperature.

Make ahead: Filling (without custard) can be made 1 day ahead and chilled once cooled. Reheat before proceeding with recipe. Pastry can be rolled out and baked 1 day ahead and kept, covered with plastic wrap, at room temperature.

Tart can be baked 3 hours ahead and cooled completely, then kept loosely covered with plastic wrap at room temperature.