Scratch the vanilla pod lengthwise, scrape out the pulp. Put milk, butter, 2 tablespoons of sugar, 1 pinch of salt, vanilla pod and pulp in a pot and bring to the boil while stirring. Remove the pot from the heat and remove the vanilla pod.
Sprinkle in semolina while stirring. Leave to swell over a low heat for approx. 3 minutes until the semolina comes off the bottom of the pot in a lump. Take it off the stove. Let it cool down. In the meantime, clean, wash, halve and stone the plums.
Boil up the plums, 80 g sugar, cinnamon stick, red wine and 150 ml water. Mix starch with a little cold water until smooth, stir into the compote and bring to the boil. Let the compote also cool down, stir several times in between.
Boil up salted water in a large pot. Whisk the egg and stir into the semolina. Form 12 small balls from the semolina mixture with moistened hands and let them simmer in the slightly boiling water for about 8 minutes.
Mix 1 tablespoon of sugar and cinnamon. Remove dumplings from the cooking water with a skimmer and drain well. Arrange three dumplings each with some plum compote on plates, sprinkle with cinnamon sugar.