- Mix espresso powder with cold water.
- Combine heavy cream, Kahlua, confectioner's sugar, and espresso. Beat until lightly whipped and soft peaks form. Reserve half and refrigerate the remaining half.
- With beater on low, mix Mascarpone and dessert sauce until smooth. Fold in reserved whipped cream until well blended and light in texture.
- Spoon mixture into demitasse cups, leaving about 1/8-inch space from the top.
- Top mixture with a dollop of remaining cream and spread out to touch the sides of the cup, creating a "faux" foam.
- Sprinkle top with espresso powder and serve a small biscotti.