Nonstick cooking spray or neutral oil • Large eggs • (1 1/2 cups, packed) Light Brown Sugar • Neutral oil (vegetable or safflower) • Vanilla extract • Kosher salt • (2 cups, lightly packed; from about 1 large or 2 small zucchini) zucchini, coarsely grated • All-purpose Flour • Unsweetened Natural Cocoa Powder • Baking Powder • Baking Soda • Bittersweet or Semisweet Chocolate Chips •