Lay a few pieces of paper towel down on two baking sheets and lay the zucchini slices on top. Salt them and top with another few pieces of paper towel. Top with another baking sheet and press down. Let sit for 10 minutes. Wipe the salt and water off of the zucchini.
In a bowl, mix together the ricotta, and 1/2 cup each of parmesan and mozzarella cheese. Season with salt and pepper, to taste, then mix in the egg.
Meanwhile, heat the oil in a large cast iron skillet. Add the garlic and saute until fragrant. Add in the spinach and allow to wilt. Season with a pinch each of salt and pepper.
Pour in the marinara sauce and give everything a stir. Reduce the sauce over the heat for 7-8 minutes until very thick.
Spread about 1 1/2 tbsp of the cheese mixture onto the slice of zucchini and roll into a pinwheel.
Ladle a few spoonfuls of the marinara sauce into the casserole dish and spread out so it covers the whole bottom of the dish.
Position all of the pinwheels into the casserole dish and top with the remaining cheese.
Place the lasagna into the oven for 15 minutes, then change the oven setting to broil.
Broil for 3-5 minutes or until golden brown.
Top with basil and enjoy!
Be sure to keep an eye on the zucchini lasagna roll ups while broiling as it can easily go from golden to burnt under a broiler.
To keep these zucchini lasagna roll ups flavourful and not watery, it's important to not skip salting the sliced zucchinis. When you salt the zucchini, it draws excess moisture from it so they don't get soggy.
I also recommend cooking down your marinara sauce so that any excess moisture will be pumped BACK into it while the zucchini lasagna cooks.