1Spray 13x9-inch (3-quart) baking dish with cooking spray. In 12-inch nonstick skillet, heat beef over medium-high heat until thoroughly cooked, stirring frequently. Drain. Stir in tomato sauce. Reduce heat to medium; cook 5 minutes, stirring occasionally.
2Meanwhile, in medium bowl, combine bell pepper and onion stir-fry, and ricotta cheese; mix well. Spoon 1/2 cup of the Alfredo sauce in bottom of baking dish. Arrange 4 uncooked lasagna noodles over sauce.
3Top with half each of the ricotta mixture, spinach, beef mixture and mozzarella cheese. Repeat with remaining noodles, ricotta mixture, spinach and beef mixture. Spoon remaining Alfredo sauce over top; sprinkle with remaining mozzarella cheese. Spray sheet of foil with cooking spray; place sprayed side down on baking dish and seal tightly. Refrigerate at least 4 hours or overnight.
4Heat oven to 350°F. Bake covered 45 minutes. Uncover; bake an additional 20 to 25 minutes or until bubbly and thoroughly heated. Let stand 5 to 10 minutes before serving.