In a large skillet, cook and stir ground beef until brown. Stir in pasta sauce, and simmer for 20 minutes.

In a medium sized bowl, combine ricotta, 1 cup of mozzarella, egg, and Italian seasoning.

Spray crock pot with cooking spray. Spoon a layer of 1) meat sauce 2) 5 uncooked lasagna noodles, broken into pieces to fit 3) ricotta cheese mixture 4) spinach.

Repeat layers one or two more times. Top with remaining meat sauce and mozzarella cheese.

Cook on low for three hours or until noodles are tender. I started checking on it at around 2.5 hours.