Dark Chocolate Sheet Cake with Peanut Butter Frosting

The classic pairing of chocolate and peanut butter is back and more indulgent than ever. In this Dark Chocolate Sheet Cake with Peanut Butter Frosting, we coated an incredibly fudgy dark chocolate cake with a generous slather of Peanut Butter Frosting.

For more epic chocolate cakes, pick up a copy of our January/February 2020 issue!

5.0 from 2 reviews
Dark Chocolate Sheet Cake with Peanut Butter Frosting
Makes 1 (13x9-inch) cake
  • 4 ounces (115 grams) 60% cacao semisweet chocolate, chopped
  • 6 tablespoons (84 grams) unsalted butter
  • 1½ cups (360 grams) water
  • 1 cup (200 grams) granulated sugar
  • 1 cup (220 grams) firmly packed light brown sugar
  • ¼ cup (21 grams) unsweetened cocoa powder
  • ⅔ cup (160 grams) sour cream
  • 1 teaspoon (4 grams) vanilla extract
  • 2 large eggs (100 grams), lightly beaten
  • 2 cups (250 grams) all-purpose flour
  • 2 teaspoons (10 grams) baking powder
  • 2 teaspoons (10 grams) baking soda
  • 1 teaspoon (3 grams) kosher salt
  • Peanut Butter Frosting (recipe follows)
  • Garnish: chopped semisweet chocolate
  1. Preheat oven to 350°F (180°C). Line a 13x9-inch baking pan with parchment paper, letting parchment extend over sides of pan. Spray parchment with baking spray with flour.
  2. In a large bowl, place chocolate and butter.
  3. In a medium saucepan, whisk together 1½ cups (360 grams) water and sugars; bring to a boil over medium-high heat, stirring occasionally, until sugar is dissolved. Whisk in cocoa. Pour over chocolate mixture, and let stand for 2 minutes. Stir until chocolate is melted and mixture is combined. Stir in sour cream and vanilla. Whisk in eggs.
  4. In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Slowly add flour mixture to chocolate mixture, whisking just until combined. Pour batter into prepared pan.
  5. Bake until a wooden pick inserted in center comes out clean, 30 to 35 minutes. Let cool completely in pan. Top with Peanut Butter Frosting; garnish with chocolate, if desired.

5.0 from 2 reviews
Peanut Butter Frosting
Makes about 5 cups
  • 1 cup (227 grams) unsalted butter, softened
  • 1 cup (225 grams) cream cheese, softened
  • 1½ cups (384 grams) creamy peanut butter
  • 1 tablespoon (13 grams) vanilla extract
  • 2 cups (240 grams) confectioners’ sugar
  • 2 tablespoons (30 grams) whole milk
  1. In the bowl of a stand mixer fitted with the paddle attachment, beat butter and cream cheese at low speed until smooth. Add peanut butter and vanilla, beating until combined. Gradually add confectioners’ sugar alternately with milk, beating until smooth. Increase mixer speed to medium, and beat until fluffy, 1 to 2 minutes.


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  1. I want to make half this recipe. Which size pan would you recommend? A 9” or 8” square? OR make whole recipe but divide into 2 pans?

    • Hey Joanna,

      Try an 8-inch pan and halve the recipe. Know that it will be a little thicker than the 9×13 version because the 8 inch will be deeper. It should bake slightly faster than the original recipe, just begin checking the cake after 25 minutes.

  2. Truly fantastic cake, I’ll use this as my chocolate cake from now on. Everyone raved about it and I’m making it for the second time in a week. Substituted Greek yogurt for sour cream and that’s the only change I made.


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