Start by mixing well the eggs with the sugar until combined fully.
Gradually incorporate the oil, whisking continuously to emulsify.
Add the sour cream the same way, bit by bit, whisking until incorporated.
Add the salt, vanilla essence, and the lemon zest.
Gradually sift in the flour, folding gently after each spoon until just incorporated.
Before the last tablespoon of flour, mix in the baking powder as well.
Preheat the oven to 170 degrees Celsius.
Pour the batter into the prepared baking tray lined with baking paper, spreading evenly.
Slice the plums into quarters.
Add the plum slices on top of the cake, one next to each other.
Bake for 35-40 minutes, until golden brown.
You can check the cake is ready by testing it with a toothpick. If it comes out clean, it’s ready.
Take the cake out of the oven, and let it cool completely before cutting.
Serve the cake cut in slices, and sprinkled with powdered sugar.