For the caramel plums, core and quarter the plums.
Melt the butter in a saucepan. Add sugar and caramelize until lightly. Gently deglaze with the amaretto and orange juice. Let simmer briefly until the caramel has dissolved again. Then add the plum pieces and a little cinnamon and simmer for about 3 minutes. Then let it cool down.
For the casserole, bring the milk, butter, sugar, vanilla sugar and lemon zest to the boil in a saucepan. Add the polenta and stir in well. Bring to the boil again briefly, remove from the stove and let cool down a little. Then stir in the quark and egg.
Grease four small portion molds (small casserole molds with approx. 200 ml content) well and distribute the polenta mixture evenly in them.
Bake in the preheated oven at 180 ° C top / bottom heat for about 30 minutes.
Carefully turn the polenta casserole onto the plates and serve with the caramel plums.