Mocha Rhum Mousse Cup Recipe

Melt chocolate and combine with espresso

Place the chopped dark chocolate in a heatproof bowl. Pour the hot brewed espresso over the chocolate and let sit 1 minute to soften, then stir until smooth and glossy. If needed, place the bowl over a simmering water bath (double boiler) briefly to finish melting. Stir in the unsalted butter until fully incorporated and glossy. Remove from heat to cool slightly (5 minutes).

Temper egg yolks and sweeten

In a small bowl, whisk the egg yolks with the granulated sugar until pale and slightly thickened. Slowly whisk about 2 tablespoons of the warm chocolate-espresso mixture into the yolks to temper, then whisk the tempered yolks back into the main chocolate mixture until fully combined and smooth. Stir in the 3 teaspoons dark rum. Set the chocolate-egg mixture aside to cool to room temperature (10–15 minutes).

Whip cream

Chill a mixing bowl and beaters for best results. Pour the cold heavy cream into the chilled bowl, add the confectioners' sugar if using, and whip to medium peaks (soft-to-firm depending on desired texture). Do not overbeat; you want the cream light and airy but still able to fold. Reserve about 2 tablespoons of whipped cream for garnish if desired.

Fold whipped cream into chocolate

Take about one-quarter of the whipped cream and whisk briskly into the cooled chocolate mixture to loosen it (lighten the chocolate). Gently fold in the remaining whipped cream in two additions using a rubber spatula with broad, gentle strokes to keep the mousse airy and homogeneous. Do not overfold—stop when no white streaks remain.

Make the coffee syrup by combining 1/4 cup cooled strong coffee/espresso with 2 teaspoons granulated sugar in a small saucepan. Warm gently until the sugar dissolves, then remove from heat and stir in 1 teaspoon dark rum. Let cool to room temperature. This syrup will be used to lightly moisten the bottom of the serving cups and to boost mocha flavor.

Prepare 4 small dessert cups (about 3–4 oz capacity each). Spoon about 1/2 teaspoon coffee syrup into the bottom of each cup and swirl to coat. Divide the mocha rum mousse evenly among the 4 cups (about 1/2 to 3/4 cup mousse per cup depending on cup size). Smooth the tops with a small offset spatula or the back of a spoon.

Chill the assembled cups in the refrigerator for at least 2 hours, preferably 3–4 hours, until set and nicely chilled. The mousse will firm up as it chills.

Shortly before serving, dust each mousse with a light sprinkle of cocoa powder, add a dollop (about 2 teaspoons) of reserved whipped cream if desired, and finish with chocolate shavings or curls. For extra aroma, brush the shavings lightly with a drop of rum or sprinkle an additional scant 1/4 teaspoon rum over each cup if serving to adults.

Serve chilled. Store leftovers covered in the refrigerator for up to 48 hours; texture may soften after prolonged storage.