Scrub and dice the potatoes, leaving the skins off for texture.
Place the diced potatoes in a large stockpot and cover with water.
Bring to a boil over high heat, and then reduce heat to medium and continue to cook until potatoes are fork tender. Stir occasionally.
Drain the potatoes in a colander and return the stockpot to the burner.
Let any water steam off of the stockpot, then add 1 Tablespoon of the butter.
Once the butter is melted and hot, add the smashed garlic and cook for 2 minutes before removing from heat.
Add the potatoes back to the stockpot, followed by the remaining butter, salt, pepper, milk, sour cream, Parmesan cheese and chives.
Use a potato masher or electric mixer to mash the potatoes.
Serve hot, with additional butter, chives and seasoning, if desired.