In a large bowl, combine the mashed potatoes, flour, sugar, salt, and yeast. Mix until combined.
Add the melted butter, egg, and water and mix until a soft dough forms.
Turn the dough onto a lightly floured surface and knead for about 10 minutes, until the dough is smooth and elastic.
Form the dough into a ball and place in a greased bowl, turning to coat all sides. Cover with a damp cloth and let rise in a warm place for about 45 minutes, or until doubled in size.
Punch down the dough and knead briefly. Shape into a loaf and place in a greased 9-inch loaf pan. Cover and let rise in a warm place for about 30 minutes, or until doubled in size.
Preheat the oven to 375 degrees F (190 degrees C).
Bake the bread for 25 to 30 minutes, or until golden brown. Remove from the oven and let cool.
Interesting Facts
Potato bread is a traditional bread of Irish and Scottish origin.
The addition of mashed potatoes to bread dough helps to create a softer, more tender texture.
This bread is delicious served with butter, jam, or honey.