Put the potatoes in a bowl and mash them.
In another bowl, add the water. If you still have the potato cooking water, you can use that, or just plain water.
Crumble the yeast and dissolve it in the water. Stir in the yogurt and honey.
Add the oats, mashed potatoes, and wheat bran, and mix well.
Mix in the wheat flour and knead the dough well on a floured surface (or using a mixer). The dough should be firm but can be slightly sticky.
Place the dough back in the bowl and let it rise overnight in the refrigerator (alternatively, 1 hour at room temperature, but then use 30g of yeast).
In the morning, preheat the oven to 200 degrees Celsius (392 degrees Fahrenheit), shape the rolls, and place them on a baking sheet with parchment paper. Let them rise for 15-20 minutes.
Brush the rolls with milk and sprinkle with oats.
Bake the rolls for 15-17 minutes, until they are golden and sound hollow when you tap on the bottom. Serve warm with a good layer of butter and a cup of tea.