Preheat oven to 400 degrees.
Using a mandoline, cut zucchini lengthwise into 1/8 inch thick slices. (You can also use a knife, just be careful!) You should have about 24 slices. Lay zucchini flat and sprinkle with salt. Let sit for at least 15 minutes. Before rolling, dab zucchini with a paper towel to get rid of excess moisture. (See note for an even less soggy way!)
In a large skillet over medium heat combine oil, crushed garlic, and onion. Saute for 2-3 minutes. Add ground turkey and cook for an additional 6-8 minutes, or until completely cooked through.
Pour 1 cup marinara sauce into the bottom of a 9-inch square baking dish.
In a medium bowl combine 1 cup mozzarella, ricotta, Parmesan cheese, egg, Italian seasonings, salt and pepper. Mix until combined. Add ground turkey mixture and stir until combined.
Place 1 ½ tablespoons of the turkey and cheese mixture along a zucchini slice. Roll zucchini slice up and place in a 9-inch square baking dish. Repeat with remaining cheese mixture and zucchini slices.
Pour remaining ½ cup marinara sauce over the roll-ups and top with 1 cup mozzarella cheese.
Bake in preheated oven for 25-30 minutes.
Serve with fresh parsley and enjoy! Serving size is 4 zucchini roll-ups.