GANACHE: 4 oz. semisweet chocolate, finely chopped 2 tablespoons (1/4 stick) unsalted butter, finely chopped 1/2 cup whipping cream Pastry Cream: 3 egg yolks 3 tablespoons sugar 2 tablespoons plus 2 teaspoons all purpose flour 1 cup milk 1 tablespoon unsalted butter 1 teaspoon vanilla Caramel Pecan Topping: 1/4 cup (1/2 stick) unsalted butter 6 tablespoons firmly packed light brown sugar 3 tablespoons sugar 1/2 cup whipping cream 1/2 teaspoon vanilla 1 cup plus 2 tablespoons lightly toasted pecans, coarsely chopped 1 egg yolk beaten with 2 tablespoons whipping cream (glaze) Chocolate curls Coarsely chopped pecans For pastry: Combine first 5 ingredients in processor. Cut in butter until mixture resembles coarse meal, using on/off turns. Combine water and vanilla; add to dry ingredients and process just until dough begins to gather together. Gather dough into ball; flatten to disc. Wrap tightly and chill 30 minutes. Roll dough out between sheets of lightly floured plastic wrap to 12-inch diameter round. Brush off any excess flour. Transfer dough to 9-inch tart pan with 1-inch high removable sides, discarding plastic wrap. Trim and finish edges. Refrigerate at least 1 hour. (Can be prepared 1 day ahead.) For ganache: Combine chocolate and butter in bowl of electric mixer. Scald cream. Add to chocolate mixture and let stand 5 minutes. Mix until chocolate melts and mixture is smooth. Pour into shallow pan. Cool. Cover and refrigerate at least 2 hours. (Ganache can be prepared 1 day ahead.) For pastry cream: Whisk yolks and sugar in small bowl until light in color. Gradually mix in flour. Scald milk in heavy small saucepan. Gradually whisk into yolks. Return to saucepan. Boil 3 minutes, whisking constantly. Mix in butter and vanilla. Strain into small bowl. Cover and refrigerate until well chilled, at least 2 hours. (Can be prepared 1 day ahead.) For topping: Melt butter in heavy medium saucepan over medium heat. Add both sugars and cook 5 minutes, stirring occasionally. Whisk in cream and vanilla; mixture will bubble up. Reduce heat to low and cook 5 minutes, stirring occasionally. Remove from heat and add 1 cup plus 2 tablespoons pecans. Cool completely. Let ganache stand at room temperature 1 hour to soften. Preheat oven to 350°F. Brush pastry with glaze. Pierce all over with fork. Bake until golden brown, about 25 minutes. Cool completely. To assemble: Spread ganache over bottom of tart shell. Refrigerate 20 minutes to firm. Cover with pastry cream. Refrigerate until set, about 30 minutes. Top with pecan mixture. Arrange chocolate curls in center of tart. Place pecans around edge. (Can be prepared 8 hours ahead and refrigerated. Let stand at room temperature 1 hour before serving.) 10 servings dess 7