Saucy Garlic Chicken

I've obviously been trying a lot of new recipes lately! Most of them have been really good. I think this one is from last month's Taste of Home.

4 whole garlic bulbs
2 T olive oil, divided
1 pkg. (9 oz) fresh baby spinach
3/4 t salt, divided
1/2 t coarsely ground pepper, divided
6 boneless skinless chicken breast halves
6 T butter
6 T flour
3 c 2% milk
2 1/2 c grated Parmesan cheese, divided
1/8 t nutmeg
Hot cooked pasta
chopped tomato and minced fresh parsley

1. Remove papery outer skin from garlic (do not peel or separate cloves). Cut tops off of garlic bulbs; brush bulbs with 1 T oil. Wrap each in heavy-duty tin foil. Bake at 425 for 30-35 minutes or until softened. Cool 10-15 minutes.
2. Meanwhile, place spinach in a greased 9X13. Sprinkle with salt and pepper. In a large skillet, brown chicken in remaining oil on both sides; place over spinach.
3. 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 2 cups of cheese, nutmeg and remaining salt and pepper. Transfer to a blender; squeeze softened garlic until smooth. Pour mixture over chicken.
4. 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 minutes longer. Serve with pasta. Sprinkle with tomato and parsley if desired.