This is another recipe from the Weight Watchers cookbook, "Slow Cook It" cookbook. Weight Watchers POINTS value = 6 points per serving; the recipe serves 6 people.
Disclaimer: I have not made this recipe, yet. I am posting it as a response in answer to others' requests for some new, different and interesting Weight Watchers recipes.
Heat a large, non-stick skillet over medium heat. Add sausage and cook, breaking it apart with a wooden spoon, until no longer pink, about 8 minutes. Transfer sausage with a slotted spoon to a plate. Add mushrooms to skillet and cook, stirring occasionally, until liquid is absorbed and mushrooms are tender, about 5 minutes.
Spray a 5- or 6-quart slow cooker with non-stick spray. Spread 1/3 cup of marinara sauce in bottom of slow cooker. Top with 6 slices of the polenta [if they don't cover the bottom entirely, that is A-OK!], half of the spinach, half of the mushrooms. Spread 1/2-cup ricotta over mushrooms and spinach. Top with half of sausage, 1 cup marinara sauce, and half of zucchini. Repeat with 6 slices of polenta, remaining spinach, mushrooms, ricotta and sausage, 1 cup marinara sauce, and remaining zucchini. Top with remaining 6 polenta slices and marinara sauce. Cover and cook until lasagna is hot and bubbling, 2-1/2 to 3 hours on high, or 5 - 6 hours on low.
Turn off slow cooker. Sprinkle lasagna with mozzarella and Parmesan. Cover and let stand 20 minutes before serving. Cut into 6 pieces.