Finally I got it right. After many failed attempts i finally succeeded in making the tarte au chocolat that i had in my head for a long time. The dough, a layer of runny caramel and a layer of soft dark rich chocolate. Try it out, you will love it.
Just one small thing, end to end, the cake will take about 3 hours to make (from which 1.5 hours it will "sleep" in the fridge)
180 gr. flour
70 gr. sugar powder
75 gr. butter
3 egg yolks
Filling (caramel layer)
250 ml heavy cream
250 gr. sugar
30 gr. honey
the seeds of one vanilla pod
Filling (chocolate layer)
120gr. heavy cream
120gr. chocolate 70%-80% cacao
Start with making the dough. Mix in a bowl the flour and the sugar powder. Add the butter in little pieces. Rub everything through your fingers till the ingredients in your bowl look like crumble. Then add the eggs, mix well and make a ball with the dough. Wrap it in plastic foil and place it in the fridge for 30 min. Preheat the oven to 160°C. Roll out the dough till it's about 3mm thick. Place it in a cake pan of about 26cm diameter. Raise the edges to about 4cm. Bake the dough for 10 minutes. Take it out of the oven and let it cool down.
Prepare the caramel layer by heating the cream, sugar, honey and vanilla in a pan. Don't stop stirring, till the sugar has dissolved completely. Reduce the heat and let it cook gently on low fire for 30 to 40 minutes. Let is cool down a little (but not too much, the caramel should still be liquid) and pour on the dough. Put the cake pan in the fridge for about 1 hour so the caramel layer can get more solid.
For the Chocolate layer, break the chocolate in pieces and place it in a bowl. Preheat the oven to 170°C. Heat up the butter, milk and cream in a pan, till it's almost boiling. Pour over the chocolate and mix till everything is melted. In a little bowl mix the eggs slightly and then add to the chocolate. Mix until everything is combined and the paste is smooth, pour it over the caramel layer very slowly in circles from the outer edge towards the middle. It is important to do this slowly, since the chocolate is heavier than the caramel, and has a tendency to push the caramel away to the edge or to mix with it. Try to avoid this in order to keep clean separate layers .
Put the cake in the oven and turn the oven down to 120 degrees. Let the cake inside the closed oven for 20 minutes. Check the consistency of the tarte by carefully shaking the pan. The chocolate should move a bit (since it is laying on the liquid caramel layer) but not too much. If the chocolate seems to runny, put it back in the oven and bake for another 5 minutes by 170 degrees. Take out and let cool down, then put in the fridge. Serve cooled.
You can keep the tarte in the fridge for several days.