Place the potatoes in a large pot and cover with water. Bring to a boil over high heat, reduce the heat to low, and simmer for 15 minutes, or until the potatoes are tender.
Drain the potatoes, reserving 1/4 cup of the cooking liquid.
Return the potatoes to the pot and mash with a potato masher or electric mixer. Add the butter, milk, sour cream, bacon, and green onion and mix until smooth.
If the potatoes are too thick, add the reserved cooking liquid. Season with salt and pepper to taste.
Serve hot.
Interesting Facts
Mashed potatoes can be made with different types of potatoes, such as russet, Yukon Gold, or red potatoes.
This dish can be made ahead of time and reheated before serving.
You can also use shredded cheese or chopped fresh herbs in place of the bacon and green onion.