These soft cookies are light and cakey, rather than dense and chewy. Still, melting chocolate chips add their own richness, while oats add texture and nutty flavor. Zucchini — though totally undetectable to either the eye (if you purée it; see baker's tips, below) or taste buds — increases the cookies' moisture level, and improves shelf life.
Preheat your oven to 350°F. Lightly grease two baking sheets; or line them with parchment.
Beat together the oil, sugar, baking powder, baking soda, salt, vanilla, and egg.
Stir in the zucchini and chocolate chips, then the flour and oats. The dough will be very sticky and moist; that's OK.
Drop the dough by tablespoonfuls onto the prepared baking sheets, leaving about 1 1/2" between them. Let the cookies rest for about 15 minutes; this gives the oats a chance to absorb some of the liquid, making them spread less. On the other hand, if you like cookies that spread flatter — bake them right away, no rest needed.
Bake the cookies for about 14 to 16 minutes, until they feel set on top. Lift the edge of one cookie; its bottom should be starting to brown. Remove the cookies from the oven, and cool them right on the baking sheets.
Place cooled cookies in a covered container at room temperature, separated by waxed paper or plastic wrap, to prevent them from sticking to one another. Store at room temperature for several days; freeze for longer storage.
