• Preheat oven to 350°F. Line a 9x13-inch pan with parchment paper, leaving an overhang for easy removal, and lightly spray with nonstick cooking spray.

Cream Cheese Swirl

• Beat the softened cream cheese and sugar until smooth and creamy. Mix in the vanilla and flour until fully combined.
• Transfer the mixture to a piping bag or a zip-top bag with the corner snipped. Set aside.

Cake Batter

• In a large bowl, mix the oil, sugar, and vanilla.
• Add the flour, cocoa powder, baking soda, and salt. Stir until the mixture is dry and crumbly.
• Fold in the shredded zucchini. Let the batter rest for 5 minutes, then stir again.
• Fold in the chocolate chips.
• Spread the batter evenly into the prepared pan. Pipe lines of the cream cheese mixture across the top of the batter. Use a knife or skewer to gently drag through the lines in the opposite direction to create swirls. A few passes are enough; do not over-swirl.
• Bake for 30 to 40 minutes, or until a toothpick inserted into the cake portion comes out with moist crumbs but no wet batter. The cream cheese areas will still look soft.
• Let the cake cool completely in the pan. For the cleanest slices and best texture, refrigerate for at least 1 to 2 hours (or overnight) before cutting.