Cook cheese tortellini according to package instructions.
Spray bottom of container with thin layer of non-stick cooking spray (I use olive oil) followed by a thin layer of marinara sauce
Add half of the cheese tortellini, marinara sauce, spinach, and cheese.
Repeat layers above and end with cheese.
Cover with plastic wrap and lid to freeze.
To bake, thaw in fridge 24-48 hours and cook at 375°F for 20-25 minutes or until cheese is golden and bubbling.