This is another one of my favorite recipes from Kraftfoods.com that's one of the easiest lasagna recipes I could find.
1 lb. ground beef (or see below for veggie version)
2 1/2 cups shredded mozzarella cheese divided in 2 equal parts (can use part-skim to cut out some fat)
1 15 oz container of ricotta cheese (can also be skim to cut out more fat)
1/2 cup grated or shredded parmesan cheese, divided in 2 equal parts
1/4 cup chopped fresh parsley (dried works fine too)
1 egg, lightly beaten
1 jar spaghetti sauce
1 cup water
12 lasagna noodles, uncooked (oven ready work best)
Heat oven to 350 degrees. Brown meat in skillet on medium-high heat. Meanwhile, mix 1 1/4 cups mozzarella with ricotta cheese, 1/4 cup parmesan, parsley and egg until well blended. Set aside.
Drain meat, return to skillet. Stir in spaghetti sauce. Add water to empty sauce jar, cover with lid and shake well. Add to meat mixture, stir until well blended. Spread 1 cup sauce onto bottom of 13x9 inch baking dish, top with layers of 3 lasagna noodles, 1/3 of cheese mixture, and 1 cup sauce. Repeat layers twice. Top with remaining noodles, sauce and cheeses (remaining mozzarella and parmesan). Cover with greased foil.
You can also substitute the meat with 1 10 oz package of frozen spinach for a vegetarian version. Just thaw spinach, squeeze out excess liquid and prepare as directed covering each ricotta mixture layer with 1/3 of the spinach.
Bake 1 hour or until heated through, removing foil after 45 minutes. Let stand 15 minutes before cutting to serve.