Melt a little butter in saucepan over medium heat and sautee mushrooms and spinach. When spinach is done, remove from heat and spread on the bottom of a 9X13 dish.
In same saucepan, melt 1/4 cup butter over medium heat. Stirring constantly, mix in the garlic, lemon juice, cream of mushroom soup, Italian seasoning, half-and-half, 1 cup of the mozzarella, and Parmesan cheese until cheese is melted.
Arrange uncooked chicken breasts in the dish on top of spinach and mushrooms, and cover with the sauce mixture.
Sprinkle with crumbled bacon.
Bake 25 minutes in the 350 degrees F (200 degrees C) oven.
Sprinkle remaining cup of mozzarella on top and continue to bake for 10 more minutes.