Grease a 9 x 14 glass baking dish with butter.
Add potatoes and 1 TBSP salt to a saucepan, cover with water.
Bring to boil and cook over medium high heat for 15 minutes.
Drain and set aside.
Whip together cream cheese and butter with a mixer for 2 minutes.
Add potatoes alternating with the half and half, whip.
Add pepper, salt, and garlic.
Pour into greased baking dish.
Top with butter before baking.
Bake at 350 for 45 minutes or refrigerate for up to 2 days.