Dough: Preheat oven to 180 C. In the bowl of a food processor, combine the flour, cocoa, sugar, salt and the butter (cold, diced) and beat until it is crumbs. Add eggs and beat until uniform. On a lightly floured surface knead dough gently until smooth. Shape it into a ball, cover with plastic foil and put in the fridge for 10 minutes. Roll out the dough into a rectangle measuring 15h40 cm and a thickness of 3 mm. Put it in shape with dimensions based 10h34 cm and cut out the excess (what goes beyond form). Put in refrigerator for 15 minutes. If you want, you can use circular and forms for cupcakes. Put the dough on baking paper and fill with rice. Bake for 10 minutes. Remove paper and rice and bake for another 5-10 minutes or until set. Filling: Preheat oven to 160 C. Put the broken chocolate and the butter cubes in a bowl. Boil the cream in a bowl. Pour the door on the chocolate and stir until chocolate is melted, add the eggs. Pour the chocolate mixture in the form of tartan - fill to 3/4 (to allow enough room for the glaze). Bake 25 minutes. Remove from oven and cool to room temperature before covering with chocolate icing. frosting: Mix cocoa, 200 ml water and sugar in a bowl and place on the stove, stirring until sugar dissolves. Bring to a boil, add the butter and stir until melted and become uniform. Strain through a strainer. Then put the broken chocolate in a large bowl. Pour the cream in a pan and put to boil. Pour the cream over the chocolate and stir until it becomes a smooth cream. Add chocolate sauce (from cocoa, water and sugar), which you have just made and mix. When finished tart cool, pour the glaze on top and put in the fridge to harden before holding.