I have tried to make garlic mashed potatoes many different ways but never could get that wonderful garlic flavor to come through until I tried it with roasted garlic. These amounts are approximate. Roasting the garlic really mellows the flavor so you can add a lot without the flavor being over-powering (in my opinion anyway).
2 to 3 lbs. potatoes (preferably gold)
4 bulbs fresh, firm garlic
approx. 1/4 cup extra virgin olive oil
12 oz can evaporated milk
1 stick unsalted butter
sea salt & pepper to taste
Trim pointy end of garlic. Place entire bulbs in small cast iron skillet. Add olive oil and cover with foil. Bake in 350 oven for about 45 minutes. Remove from oven, remove foil, and allow to cool. Once cool, remove papery skins and let garlic flesh fall into the oil. Discard papery skins and set garlic and oil aside.
Boil potatoes in salted water until tender. Drain water and immediately add butter, garlic and oil to potatoes in pot. Use electric mixer to combine and break up potatoes. Add milk slowly until potatoes reach desired consistency. You may not need the whole can and you may even want more. Season with salt & pepper to taste and serve.