Heat oven to 375 degrees F. Spray a medium baking dish with vegetable
cooking spray; set aside.
Cook noodles according to package directions, but do not add salt. Drain.
Meanwhile, spray a medium nonstick skillet with vegetable cooking
spray. Heat over medium heat.
Add beef and onion. Cook, stirring, until browned, about 5 minutes.
Place mixture on a paper towel-lined plate; drain.
In a medium bowl, combine spinach, ricotta cheese, feta cheese,
olives and 2 tablespoons mint.
Spread 1/2 cup tomato sauce in prepared
dish. Top with 3 noodles. Spread some spinach mixture over noodles.
Top with some beef mixture. Spoon 1/4 cup tomato sauce over beef
mixture. Continue layering with remaining noodles, spinach mixture,
beef mixture, and sauce.
Cover with foil. Bake until filling is heated through, about 30 minutes.