1. Mix the sugar and the butter together, add the egg and mix well, then add the flour and the cacao.

2. Roll it out and bake the mixture at 180°C for 15 minutes. Then, place in the fridge until its set.

3. Caramelize the sugar at 160°C, then add the cream and the gelatin. Cover the tart with the caramel and put it back in the fridge until it is set.

4. For the ganache, melt the chocolate, then add the cream and mix. Cover the tart with the ganache and leave it aside at room temperature.