Preheat an oven to 190 degrees C. Spray a 20cm square baking dish with cooking spray and set aside.
Mix the ricotta cheese, spinach, 1 1/2 cups Romano cheese, eggs, salt and pepper to taste in a bowl.
To assemble the lasagne, spread 1/4 cup of spaghetti sauce in the bottom of the prepared baking dish then place frozen raviolis on top in a single layer. Spread about 1 cup of the ricotta mixture over the raviolis. Repeat the layers 3 more times, ending with a layer of frozen raviolis. Spread with 1/2 cup spaghetti sauce and sprinkle remaining 1/2 cup of Romano cheese on top. Cover the dish with aluminium foil.
Bake in the preheated oven for 40 minutes until the casserole is bubbling. Then remove the aluminium foil and bake another 10 minutes to brown the cheese on top. Let sit for 10 minutes before serving.