01 -
Preheat oven to 350°F and lightly coat a 9x13-inch baking pan with nonstick cooking spray.
02 -
In a medium bowl, whisk together flour, baking soda, baking powder, salt, cinnamon, and nutmeg until thoroughly combined.
03 -
In a large bowl, whisk eggs, vegetable oil, granulated sugar, brown sugar, and vanilla extract until fully blended.
04 -
Add the dry ingredients to the wet ingredients and stir with a spoon until just combined. The batter will be thick.
05 -
Fold in shredded zucchini until evenly distributed. Stir in walnuts until fully incorporated into the batter.
06 -
Transfer the batter to the prepared baking pan and smooth the surface. Bake for 28 to 30 minutes, or until a toothpick inserted in the center comes out clean.
07 -
In a medium bowl, beat softened butter and cream cheese with a hand mixer until smooth. Add powdered sugar gradually, beating until fully combined. Scrape down the bowl with a spatula as needed.
08 -
Allow cake to cool completely in the pan. Spread the cream cheese frosting evenly over the surface of the cooled cake. Sprinkle with additional chopped walnuts if desired.
09 -
Slice into portions and serve. Store any leftovers in an airtight container in the refrigerator.