Preheat your oven to 350 degrees F. Line two baking sheets with parchment paper.

Grate the zucchini on the fine side of a box grater. Lay it out on a clean kitchen towel and press firmly to absorb the moisture. Flip the towel and press again. You want the shreds nearly dry before they go into the dough. Wet zucchini will make the cookies sticky and the fork pattern will not hold.

In a large bowl, beat the softened butter with the peanut butter, granulated sugar, and brown sugar until smooth and well combined, about 1 to 2 minutes. Add the egg and vanilla and stir until incorporated.

Add the flour, baking soda, and salt. Stir until the dough just comes together. Fold in the dried shredded zucchini until evenly distributed throughout.

Scoop tablespoon-sized portions of dough and roll into balls between your palms. Place them on the prepared baking sheets about 2 inches apart.

Dip a fork into a small bowl of granulated sugar and press down on each dough ball to flatten it slightly, then press again in the opposite direction to make the classic crosshatch pattern. The sugar on the fork keeps it from sticking.

Bake for 10 to 12 minutes, until the edges are golden and the tops look dry and set. The cookies will feel slightly soft in the center when you pull them out. That is normal and they firm up completely as they cool.

Leave the cookies on the baking sheet for 5 minutes before moving them to a wire rack. They are fragile right out of the oven and need that resting time to hold together when you lift them.