Peel and wash 2 medium sized potatoes; we like to cut ours into smaller, 1 inch sized pieces so they boil faster as well.
Place the potatoes in a pot with cold water; bring to a boil on the stove and boil the potatoes until tender, about 10 minutes.
Drain the potatoes and mash or pass through a potato ricer to get a smooth consistency with no lumps. Let cool slightly before using.
Heat up the milk, either in the microwave or in a saucepan, until it is "fingervarm" (finger warm), meaning it should feel warm to the touch but not hot. You don’t want to kill the yeast! Add the fresh yeast or active dry yeast and sugar and stir to dissolve. Let it rest 5-10 minutes until it begins to froth and bubble a little bit. (If your yeast doesn’t do anything, it may be expired. Check the expiration date on the package and start over with new yeast!) If you're using instant yeast, you can add it directly to the bowl with the rest of the ingredients instead of following this step.
Add the flour, salt, potato, sugar/milk/yeast mixture (or the sugar, milk, and instant yeast separately) to the bowl of a stand mixer or a large mixing bowl.
Knead in the stand mixer using the dough hook for about 10 minutes until the dough is smooth and elastic. If kneading by hand, combine roughly in the bowl and turn out onto a clean work surface to continue kneading. Note: you may have to add a little more water or a little more flour if your dough is either too dry or too sticky. Adjust until the dough releases from the edges of the bowl, doesn't stick to your hands, and there are no dry bits at the bottom of the bowl!
Cover the dough with plastic wrap or a damp dish towel and let rise for 45 minutes in a warm spot or until doubled in size/passes the poke test (when you poke the dough, it creates an indentation without springing back immediately).
Prepare a loaf tin by oiling the bottom and/or adding a sheet of parchment paper across the long edge of the tin, so that the paper hangs over the edge for easy removal!
Once it has doubled in size, remove the dough from the bowl onto a clean work surface. Press the dough into a rough rectangle, no wider than the length of your loaf pan.
Roll up the dough tightly (along the short edge of the rectangle) until you have a log.
Pinch together the seam at the bottom of the dough log. Now place the seam on your work surface and gently roll the dough log in circles to create tension and help close the seam.
Place the dough log into the prepared loaf tin, with the seam side down.
Cover the dough and allow to rise for another 45 minutes in a warm place until doubled in size. If using plastic wrap to cover it, we would recommend oiling the plastic where it will touch the dough so that it doesn't stick! In the meantime, preheat the oven to 350 F (176 C).
Preheat oven 350F.
Once the loaf has risen, remove the cover and brush the top with milk.
Bake for around 30 minutes or until evenly golden brown; you can also tap the loaf and if it sounds hollow, it should be baked all the way through!
Let the loaf cool for at least 30 minutes to an hour before slicing. Enjoy!