Bring a large pot of lightly salted water to a boil. Cook lasagna noodles in boiling water for 8 to 10 minutes. Drain noodles, and rinse with cold water. In a skillet over medium heat, heat olive oil. Saute onion and garlic in oil until tender. Add ground beef, and cook until evenly brown. Drain grease.
In a medium bowl, mix together stewed tomatoes, tomato paste, sugar, Italian seasoning, salt, and pepper. Spread 1/3 of the tomato mixture in the bottom of a 9x13 inch baking dish. Arrange a layer of noodles over the tomato mixture. Spread 1/2 of the remaining tomato mixture over the noodles, then top with half of the beef mixture. Dot with cream cheese, then top with 1/2 of the mozzarella cheese. Repeat layers, ending with mozzarella cheese. Cover dish with aluminum foil.
In a medium saucepan, melt butter over medium heat. Stir in flour, and cook for 2 minutes. Gradually stir in milk, and cook until thickened. Pour sauce over the top of the lasagna. Cover with aluminum foil.
Bake in preheated oven for 30 minutes. Remove foil, and bake an additional 15 minutes, or until cheese is bubbly and slightly brown.
Interesting Facts
Lasagna originated in Italy and is a type of flat pasta.
Alfredo sauce is a creamy white sauce made with butter, cream and Parmesan cheese.
The dish is also sometimes called lasagna al forno, which means "baked lasagna" in Italian.