Prepare Potatoes: Peel and quarter the red potatoes. Place them in cold water, changing the water a few times to remove excess starch.
Boil Potatoes and Garlic: In a pot, add the quartered potatoes and peeled garlic cloves. Add salt to the water. Bring to a soft boil over medium-high heat and cook until fork-tender, about 25-30 minutes.
Warm Dairy: While potatoes are cooking, warm up the whole milk, heavy cream, and butter.
Mash Potatoes: Drain the potatoes and garlic, letting them steam for 3-4 minutes. Use a ricer or food mill to mash the potatoes and garlic. Add the warm dairy mixture and stir with a rubber spatula. Season with salt to taste, being careful not to overwork the mixture.