Break the biscuits into rough pieces and divide between 4 x 125ml coffee cups or glasses. Pour over the espresso.
Melt the chocolate in a heatproof bowl set over a pan of simmering water or in the microwave.
In a medium bowl, beat together the double cream, Baileys and mascarpone until smooth and creamy. Pour over the melted chocolate and stir a couple of times until rippled. Spoon over the biscuits and serve.
Cook’s tip: for a different twist on these little chocolate pots, you can vary the liqueur – Tia Maria or Kahlúa work as well as Irish cream.