Step 1: Prepare the Oven

Preheat oven to 325°F.

Grease one 9x5-inch loaf pan or two 8x4-inch loaf pans and line with parchment paper if desired.

Step 2: Mix the Wet Ingredients

In a large bowl, whisk together:

Granulated sugar

Brown sugar

Oil

Sour cream

Eggs

Vanilla

Whisk until smooth.

Fold in the grated zucchini and let the mixture sit for about 5 minutes. This allows the zucchini to release some of its moisture, creating a softer, more tender loaf.

Step 3: Mix the Dry Ingredients

In a separate bowl, whisk together:

Flour

Baking soda

Baking powder

Salt

Cinnamon

Nutmeg

Step 4: Combine

Add the dry ingredients to the wet ingredients and gently fold together just until no dry streaks remain.

Do not overmix.

Fold in the chocolate chips (and nuts if using).

The batter should be thick but easily spreadable.

Step 5: Bake

Pour the batter into the prepared pan(s).

Sprinkle a few extra chocolate chips over the top for a bakery-style finish.

Bake:

One 9x5 loaf: 60–70 minutes

Two smaller loaves: 45–55 minutes

The bread is done when a toothpick inserted into the center comes out with a few moist crumbs but no wet batter.

If the top browns too quickly, loosely tent with foil during the last 15–20 minutes.

Step 6: Cool

Let the bread cool in the pan for 15–20 minutes, then transfer to a wire rack to cool completely before slicing.