Chocolate Mousse Tiramisu

Great suggestion for a Valentine sweet.
Classic sweet but original creation!

Ingredients for 4 portions:

3.5 oz dark chocolate, broken into small pieces

2 tbsp espresso coffee, or strong regular coffee

1 tbsp unsalted butter

2 tbsp Marsala wine (may sub with rum, or omit)

2 egg yolks

4 tsp sugar

2 tbsp mascarpone cheese

3/4 cup heavy cream, whipped