Whisk the two egg yolks with the sugar until they are pale and creamy.

Bring the cream to a boil.

Add the whisked yolks and cook up to a temperature of 90°C (200°F).

Add the coffee and stir well.

Pour the mixture over the finely chopped chocolate.

Stir until the chocolate is completely melted. 

Cool in the refrigerator.

Dice the butter and bring it to room temperature. 

Make a well in the flour and cocoa. 

Put the butter, sugar and egg into the well.

Mix the ingredients and then add the flour until you obtain a smooth dough. Refrigerate for one hour. 

Spread the dough over the base and up the edges of your cake tin. 

Use a fork to prick the bottom of the tart. 

Bake in a non-ventilated oven at 180°C (350°F) for 18 minutes.

Allow it to cool.

Using a piping bag, fill the tart with the warm Ganache cream.

Refrigerate until the cream is completely cool. 

Sprinkle with powdered sugar and serve.