Heat a large pot with several cups of water, enough to totally cover potatoes once they are put in. Bring to a boil and then add 2 tsp salt.
Prepare potatoes by cutting into cubes. I peeled the skins off the russet potatoes but not the yukon for a little bit of texture.
Add the potatoes to the boiling water and continue to boil for 15 minutes or until fork goes tenderly into potato.
While potatoes are cooking, in a saucepan, heat one stick over butter over medium heat. Add minced garlic and let cook for 2 minutes, then add in milk. Bring to a low simmer then turn off heat.
Drain potatoes, then add back to large pot.
Pour milk & butter mixture over potatoes and using a potato masher, mash potatoes very well until most large chunks are blended and the potatoes are at your desired texture.
Add in sour cream, salt, and pepper and stir until all combined. Taste test potatoes and add more salt and pepper as desired.
Top with more butter and chives before serving.