Bring a large pot of water to boil.
Break the lasagna noodles into smaller pieces, about 2-3” in length and cook according to the directions on the box. Drain the noodles and set aside.
Chop the onion and garlic into fine pieces and place it with the ground beef into a large saute pan with tall sides and cook over medium heat until browned.
Add in the sauce and the italian seasoning, salt and pepper.
Stir well and let simmer for about 10 minutes.
Preheat the oven to 350 degrees.
Line a large cookie tray (roughly 13” x 18”) with foil and spray lightly with cooking spray to prevent sticking.
Add the noodles to the saucepan and stir well.
Spoon about half the noodles and sauce onto the pan.
Cover with half of the cheese. Spread the remaining noodles.
In a medium sized bowl, mix the ricotta cheese and the spinach together.
Drop spoonfuls of the ricotta mixture over the top of the noodles on the pan.
Cover the top with the remaining cheese.
Place the pan in the oven and bake for 35-40 minutes, or until the top of the cheese starts to brown and bubble.
Remove and serve immediately.