Dissolve the yeast in the milk, add the remaining ingredients and knead the dough thoroughly. Let rise in a warm place for at least half an hour. The volume must double.
During this time, cook a pudding from milk, pudding powder and the sugar. Remove from the stove and stir in the sour cream or quark. To avoid a skin, stir the pudding mixture occasionally.
Clean and chop the rhubarb.
Knead crumble from the flour, butter and sugar.
Shape the yeast dough into small flatbreads and place on a baking sheet. Spread the cooled pudding on top, then the rhubarb and the crumble on top.
It is baked in a non-preheated oven at 180 ° C for 30 minutes.
In the meantime, stir the glaze and when the particles come out of the oven, spread the glaze on top immediately.