Preheat the oven to 350.
Cook the bacon until crispy, then set aside.
Peel and rinse the potatoes, add to a pot, and cover with water.
Bring water to a low boil and cook potatoes until fork tender.
Drain water but keep potatoes in the pot and heat on stove 1-2 minutes to release moisture.
Mash potatoes using a stand mixer, hand mixer, or potato masher until mostly smooth.
Beat in melted butter, then half and half and sour cream.
Add salt to taste and stir in 3 ounces of grated cheddar cheese.
Spread mashed potatoes into a greased baking dish.
Top with remaining 2 ounces of cheddar cheese and cooked chopped bacon.
Bake uncovered for 30 minutes.
Remove from oven and sprinkle with chopped chives.
