Step 1

Preheat the oven to 375 degrees. F Line 2 rimmed baking sheets with parchment.

Step 2

Lay out the grated zucchini on a paper-towel lined plate, to absorb as much water as possible. Set aside.

Step 3

Whisk the oats, flour, salt, baking soda and allspice together in a large bowl.

Step 4

Beat the butter and brown sugar in a separate bowl with an electric mixer (or using a stand mixer fitted with the paddle attachment) on medium speed until light yellow and fluffy, about 3 minutes. Add the egg and vanilla and mix until smooth. Add the dry ingredients to the creamed mixture and mix on low just until there's no more powdery residue, 15 to 20 seconds, then add the zucchini, chocolate chips and toasted pecans if using and mix on low until there is no dry flour in the dough.

Step 5

Use a 1/4-cup ice cream scoop to scoop the dough onto the prepared baking sheets, spacing at least 1 inch apart. Sprinkle the tops with flaky sea salt if using. Bake until the tops and sides start to brown, 15 to 20 minutes. Let the cookies cool on the sheet for at least 5 minutes, then transfer to a wire rack to cool completely. Store cookies in an airtight container for up to 1 week.