Plum cake—ready for the oven before the coffee is brewed

Ingredients:
400–500 g plums or prune plums
5 eggs
200 g sugar
2 packets vanilla sugar
375 g wheat flour (Type 405)
1 tsp salt
100 ml neutral vegetable oil
200 ml sparkling mineral water
10 g baking powder
1 tbsp vanilla extract
Zest of 1 organic lemon
15 g powdered sugar
Preparation:
1. Pit the plums and cut them into small pieces. Separate the eggs and beat the egg whites with the sugar and vanilla sugar until stiff.
2. Mix the egg yolks with the salt, oil, mineral water, vanilla, and lemon zest, then gently fold the mixture into the beaten egg whites. Fold in the flour and baking powder, pour the batter into a pan lined with
3. parchment paper, and arrange the plums on top. Bake at 180°C for about 45 minutes. Let cool and dust with powdered sugar.