Stir water, eggs, sugar and vanilla sugar until very foamy. Fold in flour mixed with baking powder.
Spread evenly on a baking tray lined with baking paper. Bake at 220°C for about 10 minutes.
Cook pudding with cherry juice.
Spread cooled custard on the cooled cake batter. Leave the cake in the refrigerator overnight so that the custard sets properly. Tip: You can also take a jar of cherries and make up to a quart with cherry juice from the jar.
After the pudding is cooked, first fold in the cherries and then pour the mixture onto the base.
