Remove garlic from skins, place in a bowl, and mash with a fork until completely mashed.
Peel and cube potatoes and place them into a large pot of cold water. Place onto stove top over high heat and bring to a boil. Once water is boiling, cook for 10–12 minutes or until potatoes are fork-tender.
Drain and transfer potatoes to the bowl of a stand mixer. Mix on low until potatoes are mashed. Add butter, Parmesan, garlic, milk, salt, and pepper. Season to taste if needed.
For thinner mashed potatoes add more milk, slowly until desired consistency.