Grate the zucchini on the large holes of a box grater. Place in a colander and sprinkle lightly with salt; toss with hands and set aside for 10 minutes. Transfer zucchini to a clean, cotton dish towel or cheesecloth and wrap tightly; squeeze a few times over a sink to remove excess water.

In a large bowl, beat the eggs. Add the zucchini, Parmesan, basil, scallions, lemon zest, garlic powder, 1 teaspoon salt and ½ teaspoon pepper. Mix with a spoon or silicone spatula to combine. Sprinkle the flour and baking powder over the mixture, then mix until no streaks of flour remain.

Line a baking sheet with paper towels. In a large, cast-iron or nonstick skillet, heat a thin layer of oil (enough to coat the bottom of the skillet) over medium heat. When hot, add ¼-cup scoops of the zucchini mixture to the skillet, pressing down gently to form 3-inch disks. Cook until browned and crisp on the bottom, 2 to 3 minutes; flip and cook until browned on the second side, 2 to 3 minutes more. Adjust heat as needed to prevent fritters from browning too quickly.

Transfer fritters to the baking sheet and sprinkle lightly with salt. Repeat with remaining zucchini mixture, adding oil as needed to the skillet.

Arrange fritters on a platter and sprinkle with more herbs. Serve immediately, with lemon wedges alongside and a dipping sauce, if using.