For the vegan yeast dumplings with vanilla sauce, heat the soy milk with the soy spread until the spread melts. Mix all ingredients for the yeast dumplings (except Powidl). Knead until the dough separates from the sides of the bowl. Let rest in a warm place for 15-20 minutes.
Then divide the dough into 8 equal pieces. Form a ball from each piece and press apart to the size of a palm. Place a teaspoon of powidl in the center of each piece, press edges of dough well together and form balls. Cover and let rise until they are about twice their size.
Meanwhile, prepare custard according to package directions with soy milk. Bring water to a boil with rum, sugar and salt; drop in dumplings and cook, covered, about 5 minutes. Turn, prick with a needle 4 to 5 times and finish cooking for another 4 minutes. Serve the vegan yeast dumplings with the vanilla sauce.