SERVES 8 TO 10
Click here for information on toasting nuts. For cutting clean slices, dip the blade of the knife in warm water and wipe with a dish towel before making each cut. See the sidebar that follows the recipe.
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WALNUT CRUST |
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1 |
large egg |
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¼ |
teaspoon vanilla extract |
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½ |
cup walnuts, toasted |
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½ |
cup (2 ounces) confectioners’ sugar |
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1 |
cup (5 ounces) all-purpose flour |
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⅛ |
teaspoon salt |
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5 |
tablespoons unsalted butter, cut into ½-inch pieces and chilled |
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CARAMEL-WALNUT FILLING |
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¼ |
cup water |
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1 |
cup (7 ounces) granulated sugar |
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⅔ |
cup heavy cream |
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3 |
tablespoons unsalted butter, cut into 3 pieces |
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½ |
teaspoon vanilla extract |
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½ |
teaspoon lemon juice |
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⅛ |
teaspoon salt |
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16–18 |
walnut halves, plus 1 cup walnuts, toasted and chopped coarse |
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CHOCOLATE FILLING |
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2 |
large egg yolks |
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1 |
tablespoon plus ⅓ cup heavy cream |
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⅓ |
cup whole milk |
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5 |
ounces semisweet chocolate, chopped fine |
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2 |
tablespoons unsalted butter, cut into 4 pieces |
1. FOR THE WALNUT CRUST: Whisk egg and vanilla together in bowl. Process walnuts and sugar in food processor until finely ground, 8 to 10 seconds. Add flour and salt and pulse to combine, about 5 pulses. Scatter butter over top and pulse until mixture resembles coarse cornmeal, about 15 pulses. With processor running, add egg mixture and continue to process until dough just comes together around processor blade, about 20 seconds.
2. Turn dough onto sheet of plastic wrap and flatten into 6-inch disk. Wrap tightly in plastic and refrigerate for 1 hour. Before rolling out dough, let it sit on counter to soften slightly, about 10 minutes. (Dough can be wrapped tightly in plastic and refrigerated for up to 2 days or frozen for up to 1 month. If frozen, let dough thaw completely on counter before rolling it out.)
3. Roll dough into 11-inch circle on lightly floured counter (if at any point dough becomes too soft and sticky to work with, slip dough onto baking sheet and freeze or refrigerate until workable). Place dough round on baking sheet, cover with plastic, and refrigerate for about 30 minutes.
4. Remove dough from refrigerator; discard plastic but keep dough on baking sheet. Loosely roll dough around rolling pin and gently unroll it onto 9-inch tart pan with removable bottom, letting excess dough hang over edge. Ease dough into pan by gently lifting edge of dough with your hand while pressing into corners with your other hand. Leave any dough that overhangs pan in place.
5. Press dough into fluted sides of pan, forming distinct seam around pan’s circumference. (If some sections of edge are too thin, reinforce them by folding excess dough back on itself.) Run rolling pin over top of tart pan to remove any excess dough. Wrap dough-lined tart pan loosely in plastic, place on large plate, and freeze until dough is fully chilled and firm, about 30 minutes, before using. (Dough-lined tart pan can be wrapped tightly in plastic and frozen for up to 1 month.)
6. Meanwhile, adjust oven rack to middle position and heat oven to 375 degrees. Set dough-lined tart pan on rimmed baking sheet. Spray 1 side of double layer of aluminum foil with vegetable oil spray. Press foil greased side down into frozen tart shell, covering edges to prevent burning, and fill with pie weights. Bake until tart shell is golden brown and set, about 30 minutes, rotating baking sheet halfway through baking. Transfer tart shell with baking sheet to wire rack, carefully remove weights, and let cool slightly while making filling. Reduce oven temperature to 300 degrees.
7. FOR THE CARAMEL-WALNUT FILLING: While crust is cooling, add water to medium saucepan, then pour sugar into center of saucepan (don’t let it hit pan sides). Gently stir sugar with clean spatula to wet it thoroughly. Bring to boil and cook, without stirring, until sugar has dissolved completely and liquid has faint golden color (about 300 degrees), 6 to 10 minutes.
8. Reduce heat to medium-low and continue to cook, stirring occasionally, until caramel has dark amber color (about 350 degrees), 1 to 3 minutes. Off heat, slowly whisk in cream until combined (mixture will bubble and steam vigorously). Stir in butter, vanilla, lemon juice, and salt until combined. Stir in walnut halves to coat. Let caramel mixture sit until slightly thickened, about 8 minutes.
9. Set wire rack over piece of parchment paper. Using slotted spoon, transfer caramel-coated walnuts to rack, flip nuts right side up, and let cool completely. Stir chopped walnuts into caramel, then pour caramel mixture into cooled prebaked tart shell. Refrigerate tart, uncovered, until caramel is firm and does not run when pan is tilted, about 20 minutes.
10. FOR THE CHOCOLATE FILLING: While caramel sets, whisk egg yolks and 1 tablespoon cream together in bowl. Bring milk and remaining ⅓ cup cream to simmer in a small saucepan. Off heat, stir in chocolate and butter, cover saucepan, and let stand until chocolate is mostly melted, about 2 minutes. Gently stir mixture until smooth, then stir in egg yolk mixture. Pour chocolate filling evenly over chilled caramel in tart shell and smooth into even layer by tilting pan. Bake tart on baking sheet until tiny bubbles are visible on surface and chocolate layer is just set, about 25 minutes.
11. Transfer tart with baking sheet to wire rack and arrange caramel-coated walnut halves around edge of tart to garnish. Let tart cool slightly on baking sheet for 30 minutes, then refrigerate, uncovered, until chocolate is firm, about 3 hours. To serve, remove outer metal ring of tart pan, slide thin metal spatula between tart and tart pan bottom, and carefully slide tart onto serving platter or cutting board.