Add the grated zucchini to a large skillet or pot and cover. Cook over medium heat, stirring occasionally, for 8–12 minutes, or until the zucchini is soft. Allow to cool completely.
Transfer the cooled zucchini to a dish towel and squeeze out as much water as possible. This step is crucial for achieving the perfect gnocchi texture!
In a large bowl, combine the zucchini, flour, cheese, and salt. Mix with a fork, then use your hands to form a pliable dough.
Lightly flour a work surface and divide the dough into 8 equal portions (about 2.75 ounces each). Roll each portion into a 10-inch rope, about 1/2-inch thick.
Cut each rope into bite-sized pieces (around 13 gnocchi per rope). Sprinkle with a little flour as needed if the dough becomes sticky.
Heat a large skillet over medium heat and generously spray with olive oil. Add half of the gnocchi in a single layer, ensuring they don’t touch. Cook undisturbed for 2 minutes, then flip gently and cook for another 2–4 minutes until golden.
Repeat with the remaining gnocchi, then toss everything back into the skillet. Pour the marinara sauce over the top and stir gently to coat. Serve hot with extra Pecorino Romano and fresh basil, if desired.