Using a large pot, cover potato cubes and garlic with water.
Bring to a boil over medium heat, reduce to low, then simmer until tender and easily pierced by sharp knife (about 30 min).
Press potatoes and garlic through a ricer.
Stir in the rest of ingredients using a wire whisk.
Serve immediately or store in an ovenproof casserole dish.
This can be prepared up to a week ahead and frozen.
If defrosted warm potatoes at 350°F for 30 minutes.
If frozen warm at 350°F for 75 minutes.
(Optional Instructions- Bring a large pot of water to a boil. Boil potatoes for about 20 minutes until tender as above. Put potatoes through ricer and combine with all other ingredients including garlic which could have been minced garlic in a jar from supermarket).