To prepare roasted garlic: Cut head of garlic in half and drizzle with olive oil. Wrap in foil and bake at 400 degrees F (200 degrees C) for 45 minutes.
Reduce oven temperature to 350 degrees F (175 degrees C).
Peel, chop and boil potatoes until tender. Drain, then mash potatoes. Add butter, milk and roasted garlic and mix in. Set aside.
Arrange chicken evenly in the bottom of a casserole dish, then sprinkle with spices, then layer peppers, corn and all but 1/4 cup cheese. Spread mashed potatoes on top, sealing everything in. Sprinkle with remaining cheese.
Bake at 350 degrees F (175 degrees C) for 25 minutes or until brown around edges.
