1

Position rack in middle of the oven. Preheat oven to 350°F. Line 12 muffin tin cups with paper liners. Spray the paper liners with nonstick spray.

2

In a medium bowl, stir the flour, baking soda, baking powder, cinnamon, and salt together. Set aside.

3

In a large bowl, whisk the eggs and sugar to blend them smoothly. Whisk in the oil and vanilla until blended. Use a large spoon to stir in the flour mixture just until incorporated. Stir in the zucchini, then stir in chocolate chips and walnuts (if using) until evenly distributed.

4

Pour about 1/3 cup of the batter into each paper liner. Bake until the tops are light brown and a toothpick inserted in center of a muffin comes out clean, about 23 minutes. If the toothpick penetrates a chocolate chip, test another spot.

5

Cool muffins in pan on a wire rack for 5 minutes. Using pot holders to protect your hands, invert the muffin pan onto a wire rack and tap the bottom to release the muffins. Turn the muffins right side up to cool for about 15 minutes and serve warm, or let cool completely, about 45 minutes.