Proof yeast in warm water, add a pinch of sugar to help activate the yeast. Combine mashed potato and boiling water. Add butter, sugar and salt . Cool to lukewarm then add yeast. Add the flour gradually, using enough to make a soft silky dough and kneed for 10 minutes. Let rise, covered, in a buttered bowl until doubled. Punch down and shape into two loaves and let rise again until almost doubled. Bake at 375 F for about 45 minutes or internal temp of 180 F, enjoy.
Recipe by KITCHEN HUI at https://kitchenhui.com/mashed-potato-bread/