For the strawberry cake, line the bottom of a 26 cm springform pan with baking paper and preheat the oven to approx. 180 °C top/bottom heat.
Beat the eggs with the sugar for a few minutes until thick and fluffy, then stir in the mineral water and the oil. Then mix the flour with the baking powder, sift and fold in.
Pour the batter into the pan, smooth it out and bake in the oven for about 25 minutes (test with a stick). The cake must cool completely until further processing.
Sort the berries, wash them, cut them into pieces if necessary and drain them. Put the sour cream, natural yogurt, sugar and vanilla sugar in a bowl and mix together.
Then whip the whipped cream until stiff, swirling in the cream stiffener. First, carefully fold the berries into the cream. Then gradually fold in the whipped cream.
Place a cake ring (optionally the baking frame) around the base and smooth the berry cream on top. The cake should now rest in the refrigerator for about 4 hours before serving.
Before serving, decorate the cake with a few strawberries.