Place the grated zucchini in a colander over a medium bowl. Sprinkle the salt on top, and set the bowl aside for 25 minutes for the salt to draw the moisture from the zucchini while you prepare the other ingredients
Tip the zucchini into a clean dishcloth or cheesecloth, and squeeze out as much of the liquid as possible. Place the drained zucchini in a clean bowl along with the onion, cheese, and egg. Mix well to combine with a spoon.
Preheat the oven to 400 °F. Line a rimmed baking sheet with parchment paper. Spoon the batter into about 8 mounds on the pan, spreading them out with wet fingers into pancake shapes. Ensure that you have at least an inch of space between latkes.
Bake the pancakes for about 30 minutes until golden all over. If desired you can flip them and bake the second side for an additional ten minutes to crisp them.
Serve immediately with a little applesauce, or freeze in portions for later.