Scrub, peel, and rinse your potatoes, then chop them into similarly sized pieces, so they finish cooking at the same time.
Step 2: Boil the potatoes
In a large pot or saucepan, put the potatoes and enough water to cover them plus an inch [2.5 centimeters] above the potatoes. Add a tablespoon of salt and garlic cloves to the water.Bring to a boil over medium heat and simmer until the potatoes are fork-tender (around 17 minutes). Drain the water, discard the garlic, and place the potatoes in a large mixing bowl.
Step 4: Mash
Using a potato masher or potato ricer, mash the potatoes, incorporating butter and milk as you go along. Start adding sour cream until the potatoes have the desired consistency.
Step 5: Season
Taste the potatoes and season with salt and pepper to taste, and serve sprinkled with chives.
Cook's notes
Russet potatoes are the preferred potatoes for mashed potatoes, but Yukon Gold potatoes works great too.