Preheat oven to 400 degrees. Slice the top off of the head of garlic, exposing all of the cloves. Drizzle with olive oil, then wrap tightly with aluminum foil. Roast for 30-40 minutes or until browned.
Peel and slice potatoes, removing any brown spots while doing so.
Place potatoes in a large pot and fill up with enough water to just cover the potatoes. Season water with salt. Bring water to a boil. Once water is boiling, reduce to a simmer and cover. Cook for 15 minutes.
Drain potatoes and return them to empty pot. Add butter, milk, salt and pepper then begin to mash. Fold in roasted garlic. Serve warm and enjoy!