Cut the potatoes into larger pieces and throw into pot of boiling water. Cook for about 15 minutes or until potatoes can be split with a fork.
While the potatoes are cooking, heat the milk, cream cheese, and garlic in a saucepan on medium heat until cream cheese is melted and sauce begins to simmer. Once it started to simmer, remove from heat.
When potatoes are done, drain them well and then mash them, leaving bigger pieces of potato if desired.
Mix in the sauce, Parmesan cheese, green onion, salt, and pepper. Serve warm.