
Preheat the oven to 350°F. Grease a 9x13 baking dish and set aside.
Peel and chop the potatoes into chunks, then boil them in salted water for 15-20 minutes until tender. Drain well.
Mash the potatoes until smooth.
Stir in butter, half-and-half, and ½ cup of cheddar cheese while the potatoes are still warm. Season with salt and pepper to taste.
Transfer the mashed potatoes to the prepared baking dish.
Sprinkle the remaining cheddar cheese on top. Bake for 25-30 minutes, or until the cheese is fully melted. Broil for an additional 4-5 minutes if desired for a golden crust.
Garnish with fresh chives and serve hot.