Preparation

• 使地壳:把面粉,糖,盐a food processor and pulse a few times to combine. Add the butter pieces and pulse until the mixture is the texture of coarse meal with some pea-size butter pieces, 5 to 7 one-second pulses. Sprinkle 2 Tbs. ice-cold water over the flour mixture and process until the dough just begins to come together in small, marble-size clumps. Don’t overprocess; the dough should not form a ball.

  Turn the dough out onto a work surface and shape it into a thick 4-inch-diameter disk. Wrap the dough in plastic and chill until firm enough to roll, about 30 minutes.

  On a lightly floured surface, roll the dough into an 11-inch circle, lifting and rotating it often, while lightly dusting the work surface and the dough with flour as necessary. Transfer the dough to a 9-1/2-inch fluted tart pan with a removable bottom. Gently press the dough into the bottom and up the sides of the pan. Roll the pin over the top of the pan to trim the excess dough. Lightly prick the bottom of the dough with a fork at 1/2-inch intervals. Refrigerate for 20 minutes to firm it up.

  Meanwhile, position a rack in the center of the oven and heat the oven to 350°F.

  Line the dough with aluminum foil and fill it with pie weights or dried beans. Put the tart pan on a baking sheet and bake for 20 minutes. Carefully lift the foil (and the weights) out of the tart pan and bake the crust until golden brown along the top edge and in some spots on the bottom, 13 to 17 minutes. Transfer the tart pan to a wire rack and cool completely. Raise the oven temperature to 375°F.

Make the caramel-almond layer

• Toast the almonds on a baking sheet in the oven until golden, 5 to 10 minutes. Let cool briefly and then chop coarsely.

  Make theBasic Caramelaccording to the directions. Immediately remove the pan from the heat and carefully add the heavy cream. The mixture will bubble up furiously. Once the bubbling has subsided, add the butter and stir until completely melted. Whisk in the vanilla, salt, and almonds until the nuts are completely coated. Pour the hot caramel mixture into the cooled tart shell, using a heatproof spatula to scrape the pot clean and distribute the nuts evenly in the shell. Let cool for 30 minutes and then refrigerate until the caramel is completely chilled, about 1 hour.

Make the chocolate layer

• Put the chocolate and cream in a small saucepan over low heat and stir occasionally until the chocolate is melted, 3 to 5 minutes. Add the butter and stir until melted and the mixture is smooth. Stir in the vanilla. Pour over the caramel layer and tilt the pan as needed to smooth the chocolate into an even layer that covers the caramel. Refrigerate until the chocolate is set, at least 1 hour and up to 1 day. Serve the tart with whipped cream or vanilla ice cream, if you like.