Was, dry and remove the stones from the plums. Preheat the oven to 180C.
Break the eggs and keep whites and yolk separate. Mix 150 gr of butter with a fork to make it really soft and creamy. Add the creme fraiche, then one by one add the eggyolka and 150 gr of brown sugar. Mix this on high speed for about 10 minutes until the mixture becomes lighter and fluffy.
Add the salt to the eggwhites and beat them to a soft peak. Carefully fold these in with the previous mixture and add the flour little by little.
Butter a form that is 22 cm wide, sprinkle with some of the brown sugar and pour in the dough. Then add the half, stoned plums, sprinkle with the rest of the sugar and put in the oven. Bak for about 40 minutes in the hot oven.
Serve either lukewarm or cold. This cake tastes best when not too well done and still a bit moist. It is quite a dense cake and I totally loved it. You can use all sorts of plums for this recipe, but make sure they are not to ripe or you will lose the slightly sour taste plus they will probably break during baking if too ripe.