Using the large holes of a box grater or a food processor fitted with the shredding disk, shred zucchini and onion.
Place zucchini and onion in a colander set over a sink, sprinkle with salt, and toss to evenly coat.
Let drain for 30 minutes, then press against the sides to extract liquid.
Wrap vegetables in a clean kitchen towel or cheesecloth and squeeze to remove excess liquid; set aside.
In a medium bowl, stir eggs, garlic, cheese, herbs, lemon zest, and several grinds of black pepper to combine, using a fork to beat well.
Add drained zucchini and onion mixture, stirring to combine.
In a small bowl, whisk flour and baking to combine; add flour mixture to zucchini mixture and, using a fork, stir until incorporated.
Line a large plate with paper towels; set aside.
In a 12-inch cast iron skillet, heat one tablespoon olive oil over medium-high heat until shimmering.
Using a scant ⅓ cup scoop or measuring cup, scoop batter onto skillet to form 3-inch pancakes spaced ½- to 1-inch apart, working in batches if necessary.
Cook until nicely browned on one side, about 3 minutes.
Carefully flip pancakes and cook until bottoms are golden brown, about 2 minutes more.
Place cooked pancakes onto prepared plate and repeat with remaining batter.
Serve with Greek yogurt, sour cream, or tzatziki, if desired.
