Decadent Double Chocolate Chip Sheet Cake

This Chocolate Chocolate Chip Sheet Cake is a celebration of deep chocolate flavor and tender, moist texture — perfect for gatherings, potlucks, or any time you want a reliable, crowd-pleasing dessert. The cake itself is rich and soft, studded with mini chocolate chips, and it’s finished with a creamy, chocolate buttercream that’s velvety and smooth. A final scatter of mini chips on top adds a little crunch and an irresistible visual finish.

Sheet cakes are ideal when you need to serve many people without fuss: they bake evenly in a large shallow pan, slice into generous squares, and transport easily. This recipe balances real chocolate intensity with simple pantry staples, so even busy bakers can achieve show-stopping results. Read on for the ingredients, step-by-step instructions, and helpful tips for the best outcome.

Ingredients

Cake:

• 2-1/2 cups all-purpose flour
• 1 (3.9 ounce) package chocolate instant pudding mix
• 1/2 cup unsweetened cocoa powder
• 2 teaspoons baking soda
• 1 teaspoon kosher salt
• 2 cups granulated sugar
• 1 cup canola oil
• 1 cup whole milk
• 1 large egg
• 1 teaspoon vanilla extract
• 1 cup water
• 1 cup mini chocolate chips

Frosting:

• 1 cup semi-sweet chocolate chips, melted and slightly cooled
• 1 cup (2 sticks) unsalted butter, softened
• 1 teaspoon vanilla extract
• 4 cups powdered sugar
• 1/2 cup unsweetened cocoa powder
• 3–4 tablespoons milk
• 1 cup mini chocolate chips, for garnish

Instructions

1. Preheat oven to 350°F (177°C). Generously spray a 12×17-inch rimmed baking pan with non-stick cooking spray and set aside.
2. In a large bowl, whisk together the flour, chocolate pudding mix, cocoa powder, baking soda, and salt until evenly combined.
3. In the bowl of an electric mixer fitted with the paddle attachment, beat the sugar, oil, milk, egg, and vanilla until smooth and well blended.
4. With the mixer on low speed, alternate adding the dry flour mixture and the water, beginning and ending with the flour mixture, until the batter is smooth and combined. Gently fold in 1 cup mini chocolate chips.
5. Spread the batter evenly into the prepared pan. Bake for 23–25 minutes, or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely in the pan on a wire rack before frosting.
6. While the cake cools, prepare the frosting. In a microwave-safe bowl, melt 1 cup semi-sweet chocolate chips until just melted (about 1 minute), stirring at the 30-second mark. Set aside to cool slightly.
7. In the bowl of an electric mixer fitted with the whisk attachment, beat the softened butter until smooth. Add the vanilla. In a separate large bowl, whisk together the powdered sugar and cocoa powder. With the mixer on low, add the powdered sugar mixture to the butter one cup at a time, mixing until a thick, slightly chunky frosting forms. Add the melted chocolate and beat until combined. Add milk one tablespoon at a time, mixing on medium-high, until the frosting reaches a spreadable consistency. Adjust with more milk if too thick or more powdered sugar if too thin.
8. Spread the frosting over the cooled cake and sprinkle the top with 1 cup mini chocolate chips. Slice into squares and serve.