It's great served with biscotti. 2 tablespoons sugar, 1 teaspoon powdered instant espresso, 2 tablespoons dark rum (optional), 1 cup (8 ounces) homemade mascarpone. 1. Mix together the sugar, expresso, and rum in a small bowl until the sugar and expresso dissolve. 2. Put the mascarpone in a medium bowl. Add the espresso mixture and mix thoroughly.