Preheat oven 400 degrees.
Cut top off garlic by about ¼ inch and remove any loose skin.
Drizzle cut open ends with olive oil & rub in.
Wrap in aluminum foil and place in baking dish.
Roast 35-40 minutes until lightly browned & looks caramelized.
Remove from oven & allow to cool about 10 minutes.
Once cool squeeze garlic out of bulb into small dish & set aside.
Meanwhile peel potatoes and rinse in cold water.
Place potatoes in large pot of salted water and cover at least 2 inches above potatoes.**
Bring to boil, then reduce to medium & cook 20-25 minutes until can easily pierce with fork.
Drain potatoes and with spoon or fork place potatoes in ricer in batches and add back to pot.
Add roasted garlic, butter, & cream cheese and mash together.
Then add greek yogurt & half & half cream and mix well.
Salt & pepper to taste.
top with optional diced green onions