Active Time

　　25 min

　　Total Time

　　45 min

　　We used store-bought graham cracker crumbs to save time; if you prefer to make your own in a food processor, you'll need 13 crackers, each about 4 3/4 by 2 1/4 inches. Freezing the tart helps to chill it quickly. If you're not in a rush, simply chill the tart in the refrigerator until you're ready to serve it.

　　

Ingredients

Makes 8 to 10 servings

　　1 1/2 cups graham cracker crumbs

　　3/4 stick (6 tablespoons) unsalted butter, melted

　　1/4 teaspoon salt

　　1 cup hazelnuts (4 3/4 oz), coarsely chopped

　　1 cup heavy cream

　　10 1/2 oz fine-quality bittersweet chocolate (not unsweetened), finely chopped

　　1/2 cup chocolate-hazelnut spread such as Nutella

　　

Special Equipment

a 9-inch (24-cm) springform pan

　　

Make crust and toast nuts:

Step 1

Put oven racks in upper and lower thirds of oven and preheat oven to 350°F. Invert bottom of springform pan (so that turned-up edge is underneath for easier removal of tart) and close side of pan onto bottom.

　　

Step 2

Stir together crumbs, butter, and 1/8 teaspoon salt in a bowl, then press onto bottom of springform pan. Bake crust in lower third of oven 7 minutes, then cool crust in springform pan on a rack.

　　

Step 3

While crust bakes, toast hazelnuts in a shallow baking pan in upper third of oven, stirring once, until golden, about 7 minutes. Transfer to a plate and cool to room temperature.

　　

Make filling while crust cools:

Step 4

Bring cream to a boil in a 1- to 2-quart saucepan, then pour over chocolate in a heatproof bowl, whisking until chocolate is melted and smooth. Whisk in chocolate-hazelnut spread until combined, then whisk in nuts and remaining 1/8 teaspoon salt.

　　

Step 5

Pour filling onto cooled crust and put in freezer until just set, about 25 minutes. (Tart should not be frozen.) Remove side of pan before serving tart.

　　Cooks' note:

　　Tart can be made 4 days ahead and chilled in pan, covered.