Step 1

Heat the oven to 350°F. Arrange a rack in the middle of the oven and heat to 350°F.

Step 2

Move the mashed potatoes to the baking dish. Transfer the potatoes into a 8x8-inch baking dish and spread into an even layer.

Step 3

Cover the potatoes with the liquid and butter. Pour the broth, cream, or half-and-half evenly over the potatoes. Add the butter in dabs, spreading them over the top of the potatoes.

Step 4

Cover baking dish with foil. Cover the baking dish with a single layer of aluminum foil. Reheat in the oven for 30 to 35 minutes.