1In a large mixing bowl, combine 1 cup of the flour, sugar, yeast, and salt.
Add the mashed potatoes, butter, and egg to the dry ingredients and mix well.
Gradually add the remaining flour, mixing until a soft dough forms.
Turn the dough onto a floured surface and knead for about 6-8 minutes until smooth and elastic.
Place the dough in a greased bowl, cover, and let it rise in a warm place until doubled in size, about 1 hour.
Punch down the dough and divide it into 12 equal pieces.
Shape each piece into a ball and place on a greased baking sheet.
Cover and let rise again until doubled, about 30 minutes.
Preheat the oven to 375°F (190°C).
Bake the rolls for 15-20 minutes or until golden brown.
Remove from the oven and let cool on a wire rack before serving.