Wash the plums, cut them in half, remove the pits, and cut the fruit into smaller pieces if you have large plums.

Grease the baking pan with butter and sprinkle with flour, or line with baking paper.

Turn on the oven to 170℃ (fan-assisted).

Mix the flour and baking powder together.

Transfer eggs and sugar to a mixing bowl and whisk together for a few minutes on high speed - until the mixture becomes very fluffy and thick.

Then add about half of the flour to the bowl and mix it briefly on low speed with the mixer.

Add oil and mix briefly.

Add the rest of the flour and mix briefly on low speed - just until combined - stop mixing when there are still remnants of flour visible near the sides.

Add the chopped plums to the batter and gently mix with a spoon.

Transfer the batter to the prepared baking pan.

Place the pan with the cake into the preheated oven and bake for about 50-55 minutes - until a dry skewer comes out clean.

After baking, let the cake cool, and before serving, you can additionally sprinkle it with a little powdered sugar.