Easy Spinach Lasagna with White Sauce

Name: Easy Spinach Lasagna with White Sauce
Ingredients: 1 (10 ounce) package frozen chopped spinach; 29 ounces Alfredo-style pasta sauce; 0.5 cup skim milk; 1 (8 ounce) package lasagna noodles; 1 pint part-skim ricotta cheese; 1 egg; 8 ounces shredded carrots; 8 ounces fresh mushrooms, sliced; 0.5 cup shredded mozzarella cheese