Bring a large pot of water to boil; add salt and cubed potatoes. Let boil for about 15 minutes until potatoes are very tender.

Drain potatoes in a colander, then add back to empty pot. Add milk, sour cream, and butter, and mash to desired consistency—either smooth and creamy or with some lumps.

Stir in chives, salt, pepper, cheese, and garlic. Serve in a family-style bowl.