Start the preparation by cutting the zucchini into as thin strips as possible (see recipe notes for tips).
After you have sliced them, salt them and arrange them on paper towels and leave them to release water for about 30 minutes.
While the zucchini is resting, prepare the meat. Heat the oil in a large cast-iron or oven-proof skillet over medium heat. Add the onions and ground beef; fry until the meat is brown. Stir in the marinara, chopped parsley and season with salt and pepper to taste.
Preheat the oven to 400 degrees Fahrenheit.
In a small bowl, combine the ricotta, parmesan, mozzarella, garlic, and finely chopped basil. Spread one tablespoon of the mixture over each zucchini strip. Roll the strips and stack them on the side until all the zucchini are used up.
Arrange the zucchini rolls on top of the meat sauce, pressing them gently into the sauce to nest. Transfer the skillet into the oven and bake for about 20 minutes, or until the zucchini get a light crust on top. Sprinkle everything with chopped fresh parsley before serving if desired.
Notes
Cut the zucchini in skinny, even slices. The thinner the cut, the easier it will be for you to roll them. To do so, cut both ends of the zucchini, then cut off enough on one side so it sits flat on the surface. Then cut lengthwise into long thin slices. Keep the edge of the knife against your knuckles so you don’t cut yourself. Lay the last piece flat, and hold the knife horizontally so you can continue cutting thin slices.
If you are not 100% confident in your knife skills to do this, and your zucchinis are small, a vegetable peeler will do the trick nicely (be sure to use the handguard for safety!). But if you do not have one, you can use a vegetable peeler as well.
The number of strips will depend on the size and thickness of your zucchinis.
Zucchini is a watery vegetable, so to ensure you do not end up with soggy lasagna, sprinkle salt over your sliced zucchini planks and let them rest in paper towels for fifteen minutes to half an hour to release all those liquids.
You can also roast or grill your Zucchini planks to make them more pliable and soft for easier rolling. If they persist on unfurling, you can secure them with toothpicks and remove those later on.
Use a light hand when rolling to make sure the cheese filling does not ooze out much. Don't worry about making your rolls perfect-they will sort themselves once you line them up on the baking pan.
Save yourself from the hassle of a messy kitchen right before a gathering or event by making this a day ahead! Just follow all steps pre-baking and cover the assembled dish with plastic wrap, then aluminum foil to prevent moisture loss. Keep it in your fridge for 24 hours and take it out to thaw for 30 minutes before baking.
Remember to let it rest for at least 10 minutes before serving.
Please keep in mind that nutritional information is a rough estimate and can vary significantly based on its products.