Melt the chopped chocolate, nougat and butter in a bowl over a warm water bath, then set aside.
Whip the cream until it is half stiff. Beat the eggs until frothy, mix in the espresso and honey. Fold the chocolate mixture and whipped cream into the egg mixture with a whisk, then pour into dessert glasses. Let cool down.
Eggnog foam:
Whip the cream very stiff, pour in the vanilla sugar, fold in the liqueur.
Pour into a piping nozzle and decorate the nougat mousse as you like. Round off the whole look with a little brittle or finely sifted cocoa powder.