Soak cherries in rum. Sift sugar; cocoa, and instant coffee together and place in a heavy sauce pan. Add the water and mix well. Bring to a boil and cook until everything is well mixed. While syrup is cooking, whip the egg yolks until light and fluffy. Reduce the speed of the beaters to the lowest level and add the hot syrup in a continuous fine stream. Continue beating until the mixture is thick and forms a ribbon pattern when the beater is pulled away. Chill well. Whip the cream with the 2 tablespoons of rum until stiff. Fold into the chocolate mixture. Fold in the chopped chocolate. Arrange foil lined paper cups in a muffin pan. Fill each cup 1/3 of the way full. Place a cherry in each cup then fill the rest of the way. Freeze at least 4 hrs. Before serving pipe whipping cream on top if desired. It will keep in the freezer for about a month.