Into a mixing bowl, add All-Purpose Flour (3 cup), Instant Dry Yeast (1 package), Salt (1 1/4 teaspoon), and Granulated Sugar (3 tablespoon). Mix to combine.
Into a mixing jug, add Milk (1 cup), Unsalted Butter (4 tablespoon), and Egg (1). Beat together until well-combined.
Pour the wet ingredients into the dry ingredients, then add the Mashed Potatoes (1/2 cup). Mix until a dough forms.
Turn the dough out onto a floured surface. Knead for 8-10 minutes, adding more flour as needed.
Place dough in a bowl. Cover and let rise for 45 minutes-1 hour, or until double in size.
Push the air out of the dough. Separate it into 11 equal pieces, each about 92 grams. Roll them into balls and place them on a baking tray lined with parchment paper, about 1/2-inch apart. Push them down to flatten.
Let dough rise for 20 minutes.
Preheat oven to 375 degrees F (190 degrees C).
Brush the tops with Milk (1 tablespoon).
Bake for 15-20 minutes.
Slice each roll in half to make buns. Use as desired.