No-Bake Chocolate Biscuit Cake
10 to 12 servings
Ingredients
For the biscuits:
1 cup (140 grams) all-purpose flour
1 1/4 teaspoons (5 grams) baking powder
Pinch of salt
6 tablespoons (90 grams) unsalted butter, softened
1/3 cup (70 grams) granulated sugar
2 large egg yolks
1/2 teaspoon (3 grams) vanilla
For the Nutella ganache:
7 ounces (200 grams) bittersweet chocolate (70% cacao), chopped finely
1 cup (240 grams) heavy cream
2/3 cup (200 grams) Nutella
10 tablespoons (150 grams) unsalted butter, cut into small cubes and softened
1/4 teaspoon (2 grams) salt
For the chocolate glaze:
1/4 cup (60 grams) cold water
2 teaspoons (8 grams) powdered gelatin
3/4 cup (150 grams) granulated sugar
1/3 cup (80 grams) water
3/4 cup plus 2 tablespoons Dutch-processed unsweetened cocoa powder
1/3 cup (80 grams) heavy cream
Method
To prepare the biscuits, sift together the flour, baking powder and salt in a mixing bowl.
In the bowl of a stand mixer fitted with the paddle attachment, cream the butter on medium speed for 1 minute. Add the sugar and beat on medium speed until light and fluffy, for about 3 minutes, scraping down the sides with a spatula as necessary. Add the egg yolks and beat until fully incorporated. Beat in the vanilla extract. Add the flour mixture and mix at the lowest speed just until combined.
Cut a large piece of parchment paper, fold it in half, then fold over the three open sides to create a 6-by-10-inch (15-by-25-cm) envelope. Unfold the envelope, place the biscuit dough in the center of the 6-by-10 inch rectangle, flatten slightly with your hand, and fold the envelope again, making sure to crease it firmly. Roll out the dough from the center to the edges until you obtain a 6-by-10 inch flat dough. Transfer it to a cutting board and chill in the freezer until firm, for about 15 minutes.
Set a rack in the middle of the oven and preheat the oven to 350°F/180°C.
Take the dough out of the freezer, peel away the top parchment and cut the dough lengthwise into 21 even strips and then crosswise into 13 even strips to yield 273 squares.
Place the biscuits on parchment-lined baking sheets, leaving about 1/4 inch (6 mm) of space between them. Bake until the tops are dark golden brown, for 12 to 14 minutes, rotating sheets from top to bottom and front to back halfway through baking. Transfer to a wire rack and cool completely.
To prepare the Nutella ganache, put the chocolate in a heatproof mixing bowl.
In a medium saucepan over medium-high heat, bring the cream to just below a boil and pour over the chopped chocolate. Let stand for half a minute, then gently stir with a spatula until completely melted. Add the Nutella and continue stirring until melted. Add the butter pieces and salt and stir until blended.
Lightly grease a 4-cup mold and line with plastic wrap, leaving two inches of overhang for easy removal. Pour 1 cup of the ganache into the mold and swirl to coat the inside.
Put the biscuits in a mixing bowl, pour over the remaining ganache and stir gently to coat the biscuits. Transfer the mixture into the mold and get rid of air pockets by rapping the mold against the counter. Cover the top tightly with plastic wrap, pressing it against the surface to create an airtight seal. Chill in the freezer until firm, for 30 to 45 minutes.
To make the glaze, pour 1/4 cup (60 grams) of cold water in a small mixing bowl, sprinkle the gelatin over the top, give it a stir, cover with plastic and set aside.
In a small saucepan over medium heat, heat together the sugar and 1/3 cup water until the sugar completely melts, stirring constantly. Take off heat, add the cocoa powder and whisk until dissolved. Stir in the heavy cream and set the pan over medium heat. Bring the mixture to a boil, remove from the heat and strain it into a heatproof bowl. Cool until an instant-read thermometer registers 130°F/55°C, for about 15 minutes.
Add the gelatin mixture and stir until completely dissolved.
Strain the glaze into a glass measuring cup and let cool until an instant-read thermometer registers 80°F/27°C, for 45 to 60 minutes, stirring occasionally.
Place the cake on a cooling rack sitting on top of a baking sheet. Pour the glaze in an even circular motion on top, starting with the sides, allowing it to cascade over and coat them completely. Start pouring in the middle and as the glaze starts going down the sides, pour the glaze about an inch from the edge to help cover the sides evenly. Reapply glaze as needed.
Allow the cake to sit until the glaze stops dripping, then transfer the cake to a serving plate and chill in the refrigerator until set, for 30 to 45 minutes.
Wrapped airtight, the cake will keep in the refrigerator for up to 1 week. Let stand at room temperature for 30 minutes before serving.
