Scrub the potatoes clean, cut into quarters and put them in a large pot. Fill the pot with cold water to completely cover the potatoes. Add 1 teaspoons of salt and bring the water to a boil.
Cook, uncovered, until fork-tender, about 15-20 minutes. Watch to make sure the potatoes don't boil over.
Drain the potatoes.
While the potatoes are cooking, heat the garlic, butter, and whole milk on low heat until steamy and fragrant, about 5 minutes.
Using a potato masher, mash the potatoes until your desired consistency. You can also use a hand mixer for creamier potatoes. Gently mix in the warm creamy garlic butter, 2 teaspoon salt, and pepper until fully combined.
Serve hot.