Step-by-Step Instructions

1. 1.Prepare the Plums

   Cut 20 plums in half and carefully remove their pits. Set aside the halved plums.

2. 2.Combine Wet Ingredients

   Crack 4 eggs into a large mixing bowl. Add 12 tablespoons of sugar and 3 tablespoons of vanilla sugar.

3. 3.Mix Eggs and Sugar

   Using an electric mixer, beat the eggs and sugars for 1 minute until the mixture is well combined, light in color, and slightly frothy.

4. 4.Add Oil and Milk

   Pour 9 tablespoons of vegetable oil and 15 tablespoons of milk into the egg mixture. Mix briefly until just combined.

5. 5.Sift Dry Ingredients

   Sift 15 tablespoons of flour and 1 tablespoon of baking powder directly into the wet mixture in the bowl.

6. 6.Form the Batter

   Mix all the ingredients with the electric mixer until a smooth, uniform batter is formed. Be careful not to overmix.

7. 7.Prepare Baking Pan

   Evenly sprinkle 5 tablespoons of sugar at the bottom of a baking pan (approximately 20x30 cm or 8x12 inches).

8. 8.Pour Batter into Pan

   Carefully pour the prepared cake batter over the sugar layer in the baking pan, spreading it evenly.

9. 9.Arrange Plums

   Place the halved plums on top of the batter, cut side down, arranging them in a decorative pattern.

10. 10.Bake the Cake

    Bake the cake in a preheated oven at 180°C (356°F) for 40 minutes, or until golden brown and a toothpick inserted into the center comes out clean.

11. 11.Invert and Serve

    Once baked, remove the cake from the oven. Immediately and carefully invert the cake onto a cutting board. Allow it to cool slightly before slicing into squares and serving.