Step 1

Set a strainer over a large bowl. Line the strainer with cheesecloth, a nut bag, or a thin kitchen towel. Grate the zucchini and onion over the cheesecloth. Sprinkle with the salt and toss to combine. Let sit for 10 minutes. Gather the cheesecloth around the zucchini mixture and squeeze out as much liquid as possible.

Step 2

Meanwhile, in a large bowl, combine the flour, baking powder, and Parmesan. Stir in the egg, milk, pepper, cumin and za'atar, if using. Stir in the zucchini mixture until combined (see Note).

Step 3

Attach a deep-fry thermometer to the side of a large, deep skillet. Heat ½-inch of oil over medium-high heat until the thermometer registers 350°F. Working in batches as needed, carefully drop ¼ cup portions of the batter into oil. Using a fork, spread the batter into thin rounds, about ¾-inch thick. Fry until golden brown and cooked through, about 3-4 minutes each side.

Step 4

Transfer to a paper towel-lined plate and sprinkle with a pinch of flaky salt. Repeat with remaining batter.

Step 5

Serve warm with tzatziki sauce alongside for dipping.