Cook brown rice, replacing water with chicken broth. Once rice is cooked, stir in oregano, salt, and pepper.
Brown sausage and drain if needed; then add marinara sauce.
Coat bottom of 9"x13" casserole dish with cooking spray or olive oil and a thin layer of marinara sauce.
In order, layer the following: zucchini, rice, cheese, and turkey sausage.
Repeat layers until all ingredients have been used (note; leave enough cheese to add as the last layer). If desired, sprinkle with a little more pepper, salt, and oregano.
Let cool completely, then cover with plastic wrap and foil to freeze.
To bake, thaw in refrigerator over night. Remove plastic wrap, cover with foil, and bake at 400°F for 30 minutes. Remove cover, and bake for another 15-20 minutes until warmed through and cheese is golden and bubbly.