Step 1

Place the potatoes and garlic in a medium (4- to 5-quart) saucepan or pot and add cold water to cover them by one inch. Stir in one tablespoon of salt and bring to a boil over high heat.

Step 2

When the water begins to boil, turn the heat down to low. Simmer the potatoes until they’re very tender but not falling apart, about 15 minutes.

Step 3

While the potatoes are cooking, melt the butter in a small (1/2- to 1-quart) saucepan or butter warmer over low heat. When the butter is melted, add the buttermilk and heat until piping-hot but not boiling, about 2 more minutes. Turn off the burner.

Step 4

When the potatoes are tender, turn off the stove and drain them a colander in the sink. Return the potatoes and garlic to the warm pot, then mash the potatoes and garlic with a potato masher until they reach your desired texture — a few lumps are just fine. Add the butter and milk mixture, season to taste with salt and pepper, and stir to combine. Transfer the potatoes to a serving bowl and serve hot.