Here is the recipe for all those who don’t have an ice cream machine. It is remarkable how much like real ice cream the texture is.
In a pyrex measuring cup, dissolve the instant coffee in the hot water and let cool. Place this coffee mixture with the semi-sweet chocolate in the top of a double boiler over simmering water on moderate heat. Stir occasionally to melt the chocolate. Remove from the heat and set aside to cool.
In the bowl of an electric mixer beat the egg yolks at high speed for several minutes until thick and light lemon-colored. Meanwhile, in a small saucepan mix the water with the sugar. Melt this mixture over low heat, stirring occasionally with a small wooden spoon, then increase heat and bring to a boil without stirring. After about 3 minutes, or when the syrup reaches 230 degrees on a candy therometer (the light-thread stage), remove heat, and without hesitation pour in a thin steady stream directly on to the egg yolks, still beating at high speed. Continue to beat for about 5 minutes more until the mixture is cool. Stir in the coffee or liqueur and the chocolate mixture, beating only until blended. Remove from mixer.
In another bowl of the electric mixer, beat the heavy cream only until it holds a very soft shape. Fold 1 cup of the cream into the chocolate mixture and then into the remaining cream. Pour into a shallow metal pan, measuring 13 x 9 x 2 inches and freeze until firm around the edges (1-1/2 to 2 hours). Meanwhile, place a large bowl and beaters of the electric mixer in the freezer. Beat the partially frozen cream in the chilled bowl until smooth. Return to the pan, cover and freeze until firm.