Bring salted water to a boil in a large pot. Add garlic and potatoes. Cook for about 15 minutes or until potatoes are cooked. (Tip: use a fork and poke one potato, if it goes in easily they're done!)
Drain water from the pot. Add in butter and about 1/2 cup of milk. Use a potato masher​ to smash potatoes.
Continue to add milk about 1/2 cup at a time until its at a consistency that you like (I prefer mine thicker so I use less milk but for a creamier texture use a bit more!).
Add salt and pepper to taste.