Warm the milk, add the sugar and crumble in the yeast. Let it sit in a warm place for 10-15 minutes. Mix the flours with the salt and the potatoes. Pour in the milk mixture. Knead well by hand for 10 minutes, cover with a kitchen towel, and let the dough rise for 40 to 45 minutes. Grease your hands and pinch tennisball-sized pieces from the dough. Let them rise on a floured board for 10 minutes. Roll out the dough to 1 cm thick and 20 cm wide, and deep fry in a pan with hot oil. Drain on paper towels and brush with garlic while it is still hot. If you like, add sour cream / crème fraîche (tejföl) and grated Emmental cheese on top.