Get a large pot of water boiling with a dash of salt. When it comes to a full boil, add the lasagna noodles and cook until al dente (soft but not soggy… about 12-15 minutes). When they are finished cooking, drain in a colander.While the noodles are boiling, prepare the filling. Thaw the package of frozen spinach in the microwave and then squeeze out as much excess liquid as possible. Combine the spinach in a bowl with the ricotta, mozzarella, parmesan, egg, freshly grated pepper and about ¼ tsp of salt. Mix until well combined.When the noodles and filling are ready to go, preheat the oven to 400°F. Prepare a glass casserole dish by spraying with non-stick spray.On a clean surface, lay out a few noodles at a time. Place a few tablespoons of filling on each noodle and spread to cover from edge to edge. The filling does not need to be thick because once the noodle is rolled up, it will be compounded. Make sure to spread it all the way to the edges of the noodles.Roll the noodles up and pl