Very thinly slice the zucchini into strips. You can do this using a mandolin, a vegetable sheet slicer or a sharp knife. The strips should be no longer than ~6-8 inches long; cut them if needed.
Lay strips on a paper or kitchen towel and sprinkle with salt. Let sit for at least 10-15 minutes until the zucchini starts to “sweat,” where water will be drawn to the surface. Pat the zucchini dry and set aside.
Whisk together the ricotta cheese, egg, nutmeg, basil, garlic and a pinch of salt and pepper.
Preheat the oven to 375 degrees F. Pour 1 cup of marinara sauce in the bottom of a large baking dish. Spread a thin layer of the ricotta mixture on the zucchini, then roll up.
Place the zucchini seam-side down in the baking sheet and repeat with the remaining zucchini. Cover with the remaining marinara sauce and cover with cheese.
Bake for 30 minutes until zucchini is soft and cheese is melted and lightly browned.