Ingredients
2 sheets refrigerated pie crust1 tablespoon olive oil1 medium red onion, thinly sliced1 tablespoon butter4 cups sliced fresh mushrooms (about 10 ounces)2/3 cup smoked salmon or lox1/3 cup crumbled feta cheese8 large eggs, divided use4 teaspoons drained capers, divided1/2 teaspoon salt, divided1/2 teaspoon pepper, divided2 teaspoons snipped fresh dill, optional, divided
Preparation
Unroll crusts into two 9-in. fluted tart pans with removable bottoms; trim edges. Refrigerate 30 minutes. Preheat oven to 400°.
Line unpricked crusts with a double thickness of foil. Fill with pie weights, dried beans or uncooked rice. Bake on a lower oven rack until edges are golden brown, 10-15 minutes. Remove foil and weights; bake until bottoms are golden brown, 2-4 minutes longer. Cool on a wire rack. Reduce oven setting to 375°.
In a large skillet, heat oil over medium-high heat. Add onion; cook and stir until tender and lightly browned, 5-7 minutes. Remove from pan. Add butter and mushrooms; cook and stir until mushrooms are tender, 6-8 minutes. Cool slightly.
Place tart pans on separate baking sheets. Divide onion and mushrooms between crusts; top with salmon and cheese. In a bowl, whisk 4 eggs, 2 teaspoons capers and 1/4 teaspoon each salt and pepper; if desired, stir in 1 teaspoon dill. Pour over 1 of the tarts. Repeat with remaining ingredients for second tart.
Bake until a knife inserted in the center comes out clean, 15-20 minutes. Let stand 5 minutes before cutting.
