Prepare the Zucchini: Start by slicing the zucchini lengthwise into thin strips. Sprinkle the strips with 1 tablespoon of salt and let them sit in a colander for about 30 minutes to draw out excess moisture. Afterward, rinse the zucchini and pat dry with a clean towel.
Cook the Meat Sauce: In a spacious frying pan, cook the ground beef on medium heat until it’s nicely browned. Once fully cooked, add the diced green bell pepper and onion, cooking until the vegetables soften. Stir in the tomato sauce, tomato paste, red wine, basil, oregano, and black pepper. Allow the mixture to cook gently for 15 to 20 minutes, letting the flavors blend beautifully. If the sauce becomes too thick, add 3 tablespoons of hot water as needed to maintain the desired consistency.
Prepare the Cheese Mixture: In a medium bowl, mix the ricotta cheese, egg, parsley, and spinach until well combined. Set this aside while you finish preparing the layers.
Sauté the Mushrooms: In a separate pan, lightly sauté the sliced mushrooms until they release their liquid and become tender. Set aside.
Assemble the Lasagna: Preheat your oven to 375°F (190°C). In a baking dish, start with a thin layer of meat sauce at the bottom. Follow with a layer of zucchini slices, then spread a layer of the ricotta-spinach mixture on top. Add a handful of sautéed mushrooms, followed by a sprinkle of mozzarella and Parmesan cheese. Repeat these layers until you run out of ingredients, finishing with a final layer of cheese on top.
Bake the Lasagna: Seal the baking dish with aluminum foil and place it in the oven for 30 minutes. After that, take off the foil and continue baking for another 15 minutes, or until the cheese is bubbly and has turned a lovely golden brown.
Rest and Serve: Let the zucchini lasagna cool for about 10 minutes before slicing. This resting time allows the layers to settle and makes slicing easier.