remove paper outer skin from garlic (don't peel or seperate cloves). cut tops off of garlic bulbs, brush bulbs with 1T oil. wrap each bulb in heavy-duty foil. bake at 425 for 30-35 min or until softened. cool for 10-15 minute
meanwhile, place spinach in a greased 9x13 baking dish, sprinkle with 1/4t each salt and pepper. in a large skillet, brown chicken in remaining oil on both sides, place over spinach.
in a large saucepan, melt butter. stir in flour until smooth, gradually add milk. bring to a boil, cook and stir for 1-2 minutes or until thickened. stir in 2c cheese, nutmeg and remaining salt and pepper. transfer to a blender, squeeze softened garlic into blender. cover and process until smooth. pour mix over chicken.
cover and bake for 30-35 minutes or until a meat thermometer reads 160 and sauce is bubbly. uncover sprinkle with remaining cheese. bake 5 min longer. serve with/over pasta. garnish with chopped tomato and parsley if desired.