Peel potatoes and cut into large chunks. Place potatoes in a large pot of boiling water along with garlic cloves. Boil for 13-15 minutes or until tender. Drain well.
Cook bacon until crisp. Set aside.
Place broccoli in a microwavable bowl, add 1 cup of water. Cover with plastic wrap and microwave 3 minutes or until tender crisp. Drain well. (Or steam broccoli on the stove if you prefer).
In a large bowl, combine potatoes, cream cheese, sour cream, butter, milk and onion powder. Mash with a potato masher. Stir in bacon, broccoli, cheddar cheese and parmesan cheese.
Spread into a casserole dish and top with remaining cheese. Bake 20-25 minutes or until heated through and cheese is bubbly.