⚪︎ Butter for the cuts (unsalted), Joshinko (or bread flour)
as needed of each
Wrap the potato in plastic wrap and microwave (at 500 W for 5 minutes). Add in one teaspoon milk (not listed), and mash until smooth. Add in milk little by little so the dough doesn't become too loose.
Place all of the ingredients aside from those marked ○ into the bread maker and press start! Leave the first rising up to the bread maker. Divide the dough into 4 portions after it is done, and roll into balls. Cover with a dampen cloth and rest for 15 minutes.
Reshape the balls, and arrange in a lightly-greased bread pan. Cover with plastic wrap and leave to rise for a second time for about 50 minutes on your oven's proofing setting, until doubled in size.
After fermenting, sift the joshinko on the dough, slice the tops of the bread, and lay the pats butter on top. Bake in 180°C oven for 30 minutes, and it's done. Cover with aluminum foil if it looks like the top is going to burn.
The baked bread is really fluffy, so take care not to squish it when removing it from the pan.
I baked this loaf in two batches. It only takes 30 minutes to for the second proof, so I recommend using a one loaf bread pan when you are short on time.
Story Behind this Recipe
I had a bunch of potatoes, so I added it to the batter to use it up.
Mash the potatoes to a similar consistency as the bread dough so that it's easy to knead into it. You can use bread flour to sprinkle the dough, but you'll have a crispier finish if you use joshinko. I quartered 10 g of butter for the top and placed them on top before baking.