Here's Julia's way for creamed garlic and garlic mashed potatoes...
Peel a head of garlic cloves. Put them in a small covered saucepan with a few tablespoons butter and cook very gently, without browning until meltingly tender. Pour in about half a cup of heavy cream, raise the heat and simmer a few minutes. Puree this mixture along with your potatoes, using more butter and cream as needed.
The cream aborbs the garlic flavor and imparts it to the potatoes.