Place your leftover mashed potatoes in an oven-safe dish, stir in butter and milk until smooth. Cover and bake at 350 degrees for 20 to 30 minutes or until heated to 165 degrees.
Coat the slow cooker insert with butter and add a small amount of milk. Stir butter and milk into your mashed potatoes before adding them to the pot. Cook on low until heated through.
Add the mashed potatoes to the top of the double boiler and stir in butter and milk. Fill the bottom pot with water and boil with the lid secured over the potatoes. Stir until heated through.
Place your potatoes in a microwave-safe bowl and stir in butter and milk. Cover and microwave for 1 minute. Stir and then microwave for another minute. Repeat until heated.
Photo: Parnis Azimi
To make mashed potatoes ahead of time, make as usual but with extra fat to stabilize the starches. To reheat, bake at 350 degrees for 30 to 40 minutes.
Photo: Megumi Nachev