Preheat your oven to 180 degrees C (350 degrees F). Prepare an 8-inch baking pan by lining it with parchment paper and lightly greasing it.

In a mixing bowl, beat the eggs with the sugar and vanilla until light and fluffy.

Add the melted butter, milk, and a pinch of salt to the egg mixture. Stir until combined.

Slowly incorporate the flour and baking powder until just combined.

Pour half of the batter into the prepared pan and spread it evenly.

Arrange half of the plum slices over the batter.

Pour the remaining batter over the plums and smooth the top gently.

Tap the pan lightly on the counter to release any trapped air bubbles.

Arrange the remaining plum slices on top, pressing them down lightly into the batter.

Dust the surface with 1-2 tablespoons of sugar.

Bake for 35-40 minutes until golden and set. A toothpick should come out clean.

Allow the cake to cool in the pan for 15 minutes before transferring it to a wire rack to cool completely.

Slice and enjoy warm or at room temperature.