PreparationFor crust: Mix flour, sugar, and salt in processor. Add butter; using on/off turns, cut in until coarse meal forms. Add 3 tablespoons ice water and egg yolk; process until moist clumps form, adding more ice water by teaspoonfuls if mixture is too dry. Gather dough into ball and flatten into disk. Wrap in plastic and refrigerate 1 hour. (Can be prepared 1 day ahead. Keep refrigerated.) Roll out dough on lightly floured surface to 12-inch round. Transfer to 9-inch-diameter tart pan with removable bottom. Trim overhang to 1 inch. Fold in overhang and press, forming double-thick sides. Chill 30 minutes. Preheat oven to 375°F. Line crust with foil; fill with dried beans or pie weights. Bake crust until light brown around edges, about 20 minutes. Remove foil and beans. Bake crust until golden brown, about 15 minutes longer. Cool 10 minutes. Maintain oven temperature. For filling: Process 1/2 cup pistachios, 1/4 cup sugar, orange peel, and baking powder in processor until nuts are finely ground, scraping down sides occasionally. Add butter and egg; process until blended. Spread frangipane evenly over bottom of crust. Toss peaches with remaining 1 tablespoon sugar in large bowl to coat. Arrange peach slices, rounded side down, in concentric circles atop frangipane, pushing slightly to adhere. Bake until frangipane is puffed and golden in center, about 55 minutes. Cool tart to room temperature. Melt apricot jam in heavy small saucepan over medium heat. Brush warm jam over peaches. Chop remaining 2 tablespoons pistachios and sprinkle over top. Cut tart into wedges and serve.
PreparationFor crust: Mix flour, sugar, and salt in processor. Add butter; using on/off turns, cut in until coarse meal forms. Add 3 tablespoons ice water and egg yolk; process until moist clumps form, adding more ice water by teaspoonfuls if mixture is too dry. Gather dough into ball and flatten into disk. Wrap in plastic and refrigerate 1 hour. (Can be prepared 1 day ahead. Keep refrigerated.) Roll out dough on lightly floured surface to 12-inch round. Transfer to 9-inch-diameter tart pan with removable bottom. Trim overhang to 1 inch. Fold in overhang and press, forming double-thick sides. Chill 30 minutes. Preheat oven to 375°F. Line crust with foil; fill with dried beans or pie weights. Bake crust until light brown around edges, about 20 minutes. Remove foil and beans. Bake crust until golden brown, about 15 minutes longer. Cool 10 minutes. Maintain oven temperature. For filling: Process 1/2 cup pistachios, 1/4 cup sugar, orange peel, and baking powder in processor until nuts are finely ground, scraping down sides occasionally. Add butter and egg; process until blended. Spread frangipane evenly over bottom of crust. Toss peaches with remaining 1 tablespoon sugar in large bowl to coat. Arrange peach slices, rounded side down, in concentric circles atop frangipane, pushing slightly to adhere. Bake until frangipane is puffed and golden in center, about 55 minutes. Cool tart to room temperature. Melt apricot jam in heavy small saucepan over medium heat. Brush warm jam over peaches. Chop remaining 2 tablespoons pistachios and sprinkle over top. Cut tart into wedges and serve.