Put flour with cocoa and powdered sugar in a large enough bowl. Add fat in egg, vanilla pulp, flakes and salt. Knead into a smooth dough, wrap in plastic wrap and refrigerate for 15 min.
For the cream, mix eggs and sugar in a saucepan. Add fat in flakes, lemon zest and juice. Stir at low temperature to form a smooth cream. Cool.
Roll out the dough on a floured surface to a thickness of about 4 mm and place it in a greased tart pan (28 cm ø). Prick bottom and edges a few times with a fork. Leave to cool for 15 minutes.
Bake on the 2nd rack from the bottom in the oven heated to 200 °C for 12 minutes (gas 3, convection oven 10 minutes at 180 °C). Cool.
Stir the mascarpone into the cream and spread on the base. Spread the kiwi, strawberry slices and orange fillets evenly over the cream.