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Moist chocolate zucchini cake squares topped with powdered sugar and chocolate chips served on a white plate with fresh raspberries and blueberries

Best Chocolate Zucchini Cake Easy Moist Chocolate Dessert - Rich, Fudgy, and Foolproof

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Prep Time 20 minutes
Cook Time 35 minutes
Total Time 55 minutes
Course Dessert
Cuisine American
Servings 12 Squares

Ingredients
  

  • 1 3/4 cups (220 g) all-purpose flour
  • 3/4 cup (65 g) unsweetened cocoa powder (natural or Dutch-process)
  • 1 1/2 teaspoons baking powder
  • 1 teaspoon baking soda
  • 1/2 teaspoon fine salt
  • 1 1/2 cups (300 g) granulated sugar
  • 1/2 cup (110 g) light brown sugar, packed
  • 2 large eggs, at room temperature
  • 1/2 cup (120 ml) neutral oil (canola, vegetable, or light olive)
  • 1/2 cup (120 ml) plain yogurt or sour cream
  • 1 teaspoon vanilla extract
  • 1/2 cup (120 ml) hot coffee or hot water
  • 2 cups (about 260 g) grated zucchini (unpeeled, gently packed)
  • 3/4 cup (130 g) chocolate chips or chopped dark chocolate (optional but recommended)
  • 1/2 cup (115 g) unsalted butter, softened
  • 2/3 cup (55 g) unsweetened cocoa powder
  • 2 1/2 to 3 cups (300–360 g) powdered sugar
  • 1/4 cup (60 ml) milk or half-and-half, plus more as needed
  • 1 teaspoon vanilla extract
  • Pinch of salt

Instructions
 

  • Prep the pan and oven: Heat oven to 350°F (175°C). Grease a 9x13-inch baking pan and line the bottom with parchment for easy removal.
  • Grate the zucchini: Use the coarse side of a box grater. Lightly fluff it with your fingers. Do not squeeze out the moisture.
  • Mix dry ingredients: In a large bowl, whisk flour, cocoa powder, baking powder, baking soda, and salt until well combined and lump-free.
  • Whisk wet ingredients: In another bowl (or the bowl of a stand mixer), whisk sugars, eggs, oil, yogurt (or sour cream), and vanilla until smooth and glossy.
  • Combine wet and dry: Add the dry mixture to the wet and stir gently until almost combined. It will be thick—this is right.
  • Add hot liquid: Pour in the hot coffee or water and whisk just until the batter loosens and becomes smooth. Don’t overmix.
  • Fold in zucchini and chocolate: Add grated zucchini and chocolate chips. Fold with a spatula until evenly distributed.
  • Bake: Pour into the prepared pan and smooth the top. Bake 30–36 minutes, or until a toothpick comes out with a few moist crumbs.
  • Cool: Let the cake cool in the pan on a rack for at least 30 minutes. Cool fully before frosting.
  • Make the frosting: Beat butter until creamy. Sift in cocoa powder; beat to combine. Add powdered sugar, milk, vanilla, and salt. Beat 2–3 minutes until fluffy, adding milk by the teaspoon if needed for spreadable consistency.
  • Frost and serve: Spread frosting over the cooled cake. Add a sprinkle of chocolate chips, sea salt, or shaved chocolate if you like. Slice and enjoy.