Cover the bottom of a cake springform pan (18 cm ø) with parchment paper. Beat eggs with sugar and 1 pinch of salt in a food processor or mixer until creamy and thick. Fold in the flour, cornstarch and lemon zest. Pour the batter into the pan, spread it out smoothly and bake in the heated oven at 180 °C (gas 2-3, convection oven 160 °C ) on the lowest rack for 12-15 minutes. Remove from the oven and cool in the pan. Remove the base from the pan and cut horizontally with a serrated knife into 2 on-the-spot thick bases. Melt raspberry jelly over low heat.
For the cream, bring milk, 125 ml whipping cream, scraped vanilla pulp, pod and sugar to a boil and simmer for 15 minutes. Remove the pod. Soak gelatine in cold water. Mix egg yolks in a whipping kettle. Stir vanilla milk with the egg yolks. Heat in a hot water bath, stirring throughout, for 6-8 min. until sauce is very creamy and thickened. Remove from the water bath. Lightly squeeze gelatin and let it melt in the custard. Pour through a fine sieve into another baking dish and cool until the sauce begins to gelatinize slightly at the rim of the vessel. Whip remaining whipping cream until stiff and fold in. Set aside to cool for 30 minutes.
Place one cake layer with the cut side up back into the mold, close the rim again. 2. place bottom with cut side up on a baking sheet and form a flexible springform rim therefore le