Mocha mascarpone cream:
6 ounces Swiss dark chocolate, finely chopped
1 1/2 cups heavy cream, divided
1 teaspoon instant espresso powder, such as Medaglia d'Oro
1/4 cup mascarpone cheese
2 tablespoons coffee liqueur
1/4 teaspoon ground cinnamon

Assembly:
One half 17 1/4-ounce box (one sheet) frozen puff pastry,
such as Pepperidge Farm
Nonstick cooking spray

Dark mocha sauce:
4 ounces semisweet chocolate, coarsely chopped
1/4 cup strongly brewed coffee
1/2 cup heavy cream
1/2 teaspoon vanilla extract
2 tablespoons coffee liqueur

Crème anglaise:
1/2 cup milk
1/2 cup heavy cream
1/2 vanilla bean, split lengthwise
3 large egg yolks
1/2 cup granulated sugar

Garnish:
Confectioners' sugar, for dusting
Cocoa, for dusting
Chocolate-covered espresso beans

 Make the white chocolate mascarpone cream:
1. Place the white chocolate in a medium bowl. In a small saucepan, bring 3/4 cup of the cream to a gentle boil. Remove from heat. Pour the hot cream
over the chocolate. Let the mixture stand for 30 seconds to melt the chocolate. Gently whisk until smooth. Whisk in the mascarpone cheese, vanilla and almond extract. Cover the mixture with plastic wrap and refrigerate for at least 4 hours.

Make the mocha mascarpone cream:
2. Place the chocolate in a medium bowl. In a small saucepan bring 3/4 cup of the cream and the espresso powder to a gentle boil. Pour the hot cream over the chocolate. Let the mixture stand for 30 seconds to melt the chocolate. Gently whisk until smooth. Whisk in the mascarpone cheese, coffee liqueur and cinnamon. Cover the mixture with plastic wrap and refrigerate for at least 4 hours.

Make the pastry layers:
3. Position a rack in the lower third of the oven and preheat to 375 degrees F. Line a baking sheet with parchment or waxed paper.
4. Thaw the sheet of puff pastry according to the package directions. Lay the sheet on a lightly floured work surface. Using a large chef's knife, trim the sheet so that it is a perfect square. Using a fork, prick the pastry well all over its surface. Using the knife, cut the sheet into four squares . Transfer the squares to the prepared baking sheet. Place the baking sheet in the freezer for 10 minutes.
5. Remove the prepared pastry squares from the freezer. Spray a wire rack which is the same size as the baking sheet with nonstick cooking spray. Place the rack upside down over the pastry squares. Bake the squares for 20 to 25 minutes, until golden. Transfer the squares to a wire rack and cool completely.
6. Using a large knife, cut each of the squares in half diagonally to form 8 triangles. Using a small knife, carefully slice each triangle in half crosswise to form two thin layers from each triangle. There will be a total of 16 triangles.

Make the dark mocha sauce:
7. Melt the chocolate with the coffee according to the directions in the Chocolate Key. In a small saucepan bring the cream to a gentle boil. Gradually whisk the cream into the melted chocolate until smooth. Stir in the vanilla and coffee liqueur. The sauce may be made up to 5 days in advance and refrigerated, covered, until serving. Reheat the sauce over simmering water before serving.

Make the crème anglaise:
8. In a heavy, medium non-corrosive saucepan, bring the milk, cream and vanilla bean to a gentle boil over medium low heat. Cover the pan, remove it from the heat and let the mixture stand for 15 minutes. Remove the vanilla bean pieces. Using a small, sharp knife, scrape the tiny black seeds from the inside of the vanilla bean into the milk mixture.
9. In a medium bowl, whisk the egg yolks and sugar until blended. Gradually whisk the warm milk mixture into the yolk mixture until blended. Return this mixture back to the saucepan. Continue cooking over medium-low heat, stirring constantly with a wooden spoon for 2 to 4 minutes, or until the custard has thickened slightly. It is done when you can run your finger down the back of the custard-coated spoon and a path remains in the custard for several seconds. Do not let the custard come to a boil.
10. Remove the pan from the heat and immediately strain the custard into a noncorrosive metal bowl. Place the bowl in a larger bowl of iced water and stir the custard for 10 to 15 minutes, or until cold. (The crème anglaise sauce may be prepared up to two days in advance, cooled, covered with plastic wrap and refrigerated.)