Preheat the oven to 180°C.
Mix the butter with the sugar and a pinch of salt. Add the eggs yolk and then the flour. Mix well but do not overwork the pastry. Line individual tartlet cases with the pastry and then chill for 30 minutes.
Prick the pastry with a fork and then bake in the oven for 15 minutes. The pastry should be a light golden brown colour when removed from the oven.
Bring the cream to the boil. Break the chocolate into pieces and then add the hot cream. Mix gently until all the chocolate has been incorporated and you have a smooth ganache. Pour the ganache into your pastry cases and then chill for 1 hour.
Make the cappuccino cream: dissolve the sugar in the hot coffee and then allow to cool. Add the coffee to the mascarpone and mix until smooth. Place the cappuccino cream in a piping bag and then pipe on top of the set chocolate ganache.
Chill until ready to serve.
«Feel free to blind bake the pastry to make sure that it does not rise when cooked.»