10 whole graham crackers (1-1/2 cup crumbs)
6 tablespoons butter
¼ cup chopped chocolate
2 tablespoons Nutella
12 ounces semisweet or bittersweet chocolate
1-1/4 cup heavy cream
2 teaspoons instant espresso powder
1/2 cup sugar
2 large egg whites
Crust: Preheat oven to 350°F. Butter a 9-x13-inch baking pan. In a food processor, grind the graham crackers to a fine meal. Put the butter, chocolate, and Nutella in a large glass bowl and microwave on high for 30 seconds. Stir and cook for another 30 seconds or until the mixture is melted; stir until smooth. Add the graham cracker crumbs and mix well. Press the mixture into the bottom of the prepared pan and bake until lightly browned and firm, 10 to 12 minutes. Remove from oven and cool.
Filling: Finely chop the chocolate and put it in a medium glass bowl. Heat the cream and espresso powder together in the microwave or in a saucepan on top of the stove until boiling. Pour over the chopped chocolate and allow to sit for 2 minutes without stirring. Whisk the mixture together until smooth. If there are still some unmelted pieces of chocolate, put the bowl in the microwave for 20 seconds and stir again. Pour the filling over the crust and refrigerate until firm, about one hour.
Topping: Stir together 2 tablespoons of water and sugar in a glass measuring cup. Heat in the microwave until the temperature is 180°F, about 1 minute and 30 seconds. In the bowl of an electric mixer, beat the egg whites until frothy. Slowly add the sugar syrup and beat until the mixture is cool and meringue is stiff and shiny. Spread the meringue onto the cooled chocolate. Serve as is, or, with a blowtorch, toast the meringue until golden brown. Cut into squares.