Boil the russet potato until soft, then cool until it is room temperature. Mash finely or rice and add to flour and salt in a large bowl
Heat the milk for just a few seconds in a microwave until it is lukewarm. Mix in the sugar and bloom the yeast in this mixture.
Combine the wet and dry ingredients in the mixer bowl and mix until it comes together. If you need to, add just a tiny bit of water but not much.
Knead until the dough is smooth and supple. This took me around 15 minutes at medium speed in my KitchenAid, along with a few sessions of manual kneading on the tabletop.
Put dough intp oiled bowl. Cover and let rise for 45 minutes to an hour
Divide into 8 equal pieces, pinch closed on bottom and roll into a round breadroll shape.
Keeping the pieces you are not working with covered, pat out and flatten each breadroll shape and roll out to a circle around 6″ in diameter, then cover.
Proof the flattened dough for 20-30 minutes while the oil heats to ~350° F.
Working with one dough disk at a time, stretch them like a pizza dough, starting with your hands in a steering wheel orientation, then moving to using your knuckles. Stretch each piece of dough to 8″ or 9″ in diameter, so that it has a thin center with a slightly thicker outer rim like a less pronounced cornicione. Fry the dough for a couple of minutes on each side until nicely brown in color.