Active Time

　　40 min

　　Total Time

　　3 1/2 hr

　　This frozen dessert, based on the sweet flavors of Vietnamese coffee, will have adults clamoring like children. Each slice delivers an over-the-top mix of ice cream, fudge, and cookie crust.

　　

Ingredients

Makes 10 servings

　　

For crust

3/4 cup chocolate wafer crumbs (from about 15 cookies such as Nabisco Famous Chocolate Wafers)

　　1 teaspoon instant-espresso powder

　　2 tablespoons unsalted butter, melted

　　

For ice cream layer

1 pt premium coffee ice cream, softened slightly

　　1 pt premium coconut sorbet, softened slightly

　　

For fudge sauce

3 tablespoons heavy cream

　　1 tablespoon light corn syrup

　　1 tablespoon packed dark brown sugar

　　1 teaspoon unsweetened Dutch-process cocoa powder

　　1/8 teaspoon salt

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

　　1 tablespoon unsalted butter

　　1 teaspoon vanilla

　　

Special Equipment

a 1 1/2-qt rectangular mold such as a 12- by 3 1/4- by 2 3/4-inch pté mold; parchment paper; an offset metal spatula

　　

Make crust:

Step 1

Put oven rack in middle position and preheat oven to 375°F.

　　

Step 2

Line mold with a double layer of parchment paper, allowinga few inches of overhang along each side.

　　

Step 3

Stir together crumbs, espresso powder, and butter and press over bottom of mold. Bake until crisp, about 10 minutes, then cool completely in mold on a rack, about 20 minutes.

　　

Make ice cream layer:

Step 4

Scoop and drop ice cream and sorbet alternately into mold in 1 layer until crust is covered, then smooth with offset spatula until flat. Make another layer in same manner. Freeze, covered with plastic wrap, until firm, at least 2 hours.

　　

Make fudge sauce and finish cake:

Step 5

Bring cream, corn syrup, brown sugar, cocoa, salt, and half of chocolate to a boil in a 1- to 1 1/2-quart heavy saucepan over moderate heat, stirring until chocolate is melted. Reduce heat and simmer, stirring occasionally, 5 minutes, then remove from heat.

　　

Step 6

Add butter, vanilla, and remaining chocolate and stir until smooth.

　　

Step 7

Cool fudge sauce to warm, at least 15 minutes.

　　

Step 8

Pour warm sauce over ice cream layer and freeze again, uncovered, until firm, about 15 minutes. Remove cake by grasping both ends of parchment, and transfer it to a platter. Using a spatula to stabilize end of cake, carefully slide parchment out from under cake.

　　Cooks' notes:

　　·Sauce can be made 1 week ahead and cooled completely, uncovered, then chilled in an airtight container or jar. Reheat before using.

　　·Cake keeps, wrapped well in plastic wrap and then in foil, 3 days.