1 Tbs butter
1 large onion, chopped
6 cups leftover mashed (cooked) potatoes (or freshly made)
2 (14.5 ounce) cans chicken broth
1/2 cup milk
In a medium soup pot melt butter over low heat, and saute onions until tender.
Stir in the mashed potatoes, and then slowly add the chicken broth.
Stirring, add milk (use more or less to achieve desired creaminess).
Cook until heated through and season with salt and pepper to taste.