To make the ice cream
Beat the cream until thick. In a separate bowl, beat the condensed milk and mascarpone until smooth. Dissolve the coffee in a splash of boiling water and add to the condensed milk mixture. Fold in the whipped cream. Transfer to a plastic container with a tight-fitting lid and freeze.
To make the mousse cake
Preheat the oven to 220 °C. Grease and line the base and sides of a 23 cm springform cake tin with baking paper. Place the chocolate, butter and condensed milk in a saucepan over low heat, stirring until the chocolate and butter melts. Allow to cool slightly. Beat in the egg yolks. Beat the egg whites until stiff. Fold the flour into the chocolate mixture, then gently fold in the egg whites. Pour the batter into the prepared cake tin and bake for about 15 minutes. Cool and refrigerate.
To serve, slice the cake and serve with a scoop of the coffee ice cream. Decorate with chocolate-covered coffee beans, if desired.
Recipe from Condensed Milk: everyone’s guilty secret, by Cleta Joannou, published by Human & Rousseau.