For the cake:
Preheat the oven to 350°F. Butter the bottom and sides of a 10-inch round cake pan, and line the bottom of the pan with parchment paper. Set aside.
Melt the chocolate, butter, and dissolved coffee in the top of a small double boiler set over medium heat. Stir until just melted and smooth. Remove from the heat and set aside to cool.
In a medium bowl, combine the egg yolks, ground almonds, cooled chocolate mixture, brown sugar, and vanilla extract, whisking to combine. Set aside.
In a standing mixer or using a hand mixer, beat the egg whites on low speed until bubbles start to form. Add the salt to the whites and gradually increase the speed to medium-high. As the eggs become white, slowly add the sugar, beating until the whites are glossy and can hold a firm peak. Using a rubber spatula, stir one large spoonful of the whites into the almond-chocolate mixture. Fold in the remaining egg whites in three additions, until white streaks are barely visible.
Pour the batter into the prepared pan, leveling the top of the mixture with a spatula.
Bake for 40 minutes, or until a tester inserted in the center comes out clean.
Once the cake reaches room temperature, cover it with aluminum foil and chill it in the refrigerator for up to 3 hours.
While the cake is chilling, prepare the Shiny Mocha Glaze: Combine the chocolate and butter in a medium stainless-steel bowl, set on a double boiler. Stir until almost melted, then add the hot cream with the coffee dissolved in it. Let cool to warm before frosting the cake.
Using a rubber spatula, spread a spoonful of the warm glaze on top of the chilled cake. Using a small offset spatula, smooth it across the top and sides. Refrigerate the cake for about 15 minutes to set the glaze. Serve immediately, or keep the cake refrigerated, removing it from the refrigerator 1½ hours before serving.
Once the glaze hardens, brush the top and sides of the cake with gold metallic powder, if desired.