Birthday Chocolate Sheet Cake

Prep Time 1 hour 10 minutes
Cook Time 30 minutes
Total Time 1 hour 40 minutes
Servings 12 servings


  • 1-1/3 cups semisweet chocolate chips
  • 3/4 cup butter softened
  • 1 cup coconut sugar or brown sugar
  • 4 large eggs room temperature
  • 2 teaspoons vanilla extract
  • 1 cup buttermilk
  • 1 cup white whole wheat flour
  • 3/4 cup unsweetened cocoa powder
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon salt
  • 1 cup semisweet chocolate chips
  • 1/2 cup heavy whipping cream
  • Mini chocolate chips/decoration of your choice optional


  1. Preheat oven to 325F. Line a 13x9 baking pan with parchment paper. Set aside.
  2. In a double-boiler over medium-high heat, melt chocolate and butter, whisking occasionally until smooth. Remove from heat and cool slightly.
  3. Meanwhile, in a large bowl, whisk sugar, eggs, and vanilla until smooth. Whisk in buttermilk and cooled chocolate mixture. In a separate large bowl, combine flour, cocoa, baking soda, and salt. Gently fold flour mixture into liquid, stirring until just combined (do not overmix) Batter will be slightly on the thinner side.
  4. Pour batter evenly into prepared pan. Bake sheet cake at 325F 30-35 minutes or until a toothpick comes out with moist crumbs sticking to it. Cool completely on a wire cooling rack.
  5. Make the frosting: Place chocolate chips in a small saucepan, melt over medium heat until chips just start to lose their shape. In a separate saucepan, heat cream until just simmering. Pour hot cream over chocolate chips and whisk until smooth and combined. Place frosting in refrigerator to cool for about 1 hour.
  6. Once frosting has chilled, transfer to a medium bowl. With a handheld electric mixer, beat on high speed until soft peaks form and frosting is thick and creamy.
  7. Immediately spread frosting over cooled cake and sprinkle with decor of your choice if desired.

Recipe Notes

Store cake in an airtight container at room temperature up to 4 days.