For the chocolate tart, first mix flour with cocoa for the chocolate shortcrust pastry and sift onto a work surface. Add the remaining ingredients in order and knead with your hands to form a dough. Refrigerate, wrapped in plastic wrap, for about 1/2 hour.
Roll out the dough on a floured work surface into a round (36 cm Ø). Place the dough in a greased, floured tart pan (30 cm Ø). Spread the lentils on the dough for blind baking.
Place the pan on the rack in the middle of the preheated oven and pre-bake the dough.Top/bottom heat: 190 °Hot air: 170 °CBaking time: approx. 10 min.
Hold the overcooled pan at an angle and remove the loose lentils with a spoon. Sticking lentils can be loosened with the spoon.
For the chocolate royal filling, place the ingredients in order in a saucepan and heat while stirring; the mixture should not boil. Pour the warmed mixture onto the shortbread.
Place the pan on the rack in the center of the oven.Top/bottom heat: approx. 180 °Hot air: approx. 160 °CBaking time: approx. 20 min.
Sprinkle the chocolate tart with cocoa before serving.
A dollop of whipped cream goes well with the chocolate tart.