Heat oven to 350°F. Spray 12x8- or 11x7-inch (2-quart) glass baking dish with cooking spray. Cook noodles as directed on package. Drain; rinse with hot water.
Meanwhile, in 10-inch skillet, cook beef over medium-high heat 5 to 7 minutes, stirring occasionally, until thoroughly cooked; drain. Stir in pasta sauce and cooked noodles.
In medium bowl, beat cream cheese, sour cream and milk with spoon until smooth.
Spoon half of the noodle mixture into baking dish. Top evenly with cheese mixture. Spoon spinach evenly over cheese mixture. Top with remaining noodle mixture. Cover with foil.
Bake 35 minutes; uncover and sprinkle with Parmesan cheese. Bake about 5 minutes longer or until hot. Cut into squares.