Cook pasta and reserve 1 ladel of pasta water. Toast walnuts for 4-5 minutes. Cool. Add walnuts, garlic, parsley and spinach to food processor or blender and chop. Slowly add oil until thick paste. Add sauce, pasta water and parmesan cheese to bowl and mix. Add ricotta and honey. Add pasta and toss. Place pasta in baking dish and cover with mozzarella. Bake until cheese is melted.