Season 250 ml milk with a pinch of salt and sugar and bring to the boil. Add rice to the boiling milk and cook until al dente, depending on the type of rice and the instructions on the package (usually approx. 10-15 minutes).
In the meantime, mix the remaining 100ml milk with the cornstarch and vanilla sugar (or just 10g vanilla pudding powder instead) and stir into the boiling milk when the rice is done. Let simmer for a minute and sweeten as you like and serve with cherries or cinnamon and sugar.