Peel and cut the potatoes into evenly-sized chunks, about 1 to 2 inches thick. Place the potatoes in a large stockpot and add enough cold water to cover them by about 2 to 3 inches. Add 1 tablespoon of salt to the water.

Bring the water to a boil over high heat. Reduce heat to medium-high and cook for about 15 to 20 minutes, or until a fork easily pierces the potatoes.

While the potatoes cook, heat 1 cup of butter, 1 cup of half-and-half, and 1 cup of milk in a separate saucepan until the butter melts and the mixture is hot but not boiling.

Drain the cooked potatoes and return them to the pot. Pour the warm butter and milk mixture over the potatoes. Mash with a potato masher or ricer until smooth, then gently fold with a wooden spoon or spatula to combine.

Spread the mashed potatoes into a greased 9x13-inch baking pan. Dot the top with an additional 2-4 tablespoons of butter, if desired. Cover tightly with plastic wrap and foil. Refrigerate for up to 2 days.

When ready to serve, preheat the oven to 350°F (175°C). Remove plastic wrap, keeping the foil on, and bake for 25-30 minutes. For a golden top, remove the foil in the last 10 minutes. Serve warm and enjoy!

Follow steps 1 to 4 above, preparing the mashed potatoes on the stovetop.

Once the potatoes are mashed and seasoned, transfer them to a greased slow cooker insert. Dot the top with an additional 2-4 tablespoons of butter, if desired.

Cover the slow cooker and set it to Low for up to 4 hours to keep the potatoes warm and creamy. Stir occasionally to prevent them from drying out.