Preparation of the Ganache Cream
Mix two egg yolks with the sugar and whisk until light and creamy.
Bring the double cream to a boil.
Add the whisked yolks and cook up to 194°F (90°C).
Add the coffee and mix well.
Dice the chocolate into small pieces, and pour the mixture over the chocolate.
Mix until the chocolate has completely dissolved.
Place in the fridge until chilled.
Dice the butter and bring to room temperature.
Meanwhile, form a fountain shape with the flour and cocoa powder.
Place the butter, sugar and egg in the center of the fountain.
Knead the ingredients and then add additional flour until the mixture is smooth. Place in the fridge for 1 hour.
Lay the pastry over the base and sides of your baking tin.
Use a fork to prick the base of the tart.
Cook in a conventional oven at 356°F (180°C) for 18-20 minutes.
Allow to cool.
Using a pastry bag, pour the lukewarm ganache cream over the tart.
Place in the fridge until the cream is completely chilled.
Sprinkle icing sugar on top and serve.