Preheat the oven to 350°F. Coat an 8×8-inch pan with nonstick cooking spray and line with parchment paper.
Cut the stems off the zucchini. Grate the zucchini with a box grater or food processor.
Place the grated zucchini onto a clean kitchen towel and squeeze out as much liquid as possible. Measure 1 cup tightly packed grated zucchini.
Add the zucchini to a medium bowl with the eggs, flour, cheese, baking powder, salt, and onion powder.
Stir well until a uniform batter forms.
Pour the batter into the prepared baking pan.
Bake for 25–30 minutes, or until the edges are lightly golden brown and the top is firm and set.
Cool slightly, then remove from the pan and slice into sticks or squares with a serrated knife.