Mix all ingredients to make the sponge cake batter. Butter a springform pan and dust with flour. Pour the batter into the pan and distribute evenly. Bake in pre-heated oven at 180°C/350°F for approx. 20 min. until golden.
Follow packet instructions to make the vanilla custard. Then set aside to cool.
Wash the strawberries. Place the sponge cake on a cake plate, then put a cake ring around it. Remove the skin on top of the custard, then evenly distribute on top of the sponge cake. Neatly arrange strawberries on top of the custard layer.
Follow packet instructions to prepare the jelly and use a tablespoon to evenly spread it on top of the strawberries. Put the cake in the fridge for at least 1 h. Serve with whipped cream.