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A peanut butter cake with two square slices cut, on a piece of parchment.
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Peanut Butter Cake

This melt-in-your-mouth peanut butter cake topped with the most amazing buttercream ever is a quick and easy treat you'll make over and over.
Course Dessert
Cuisine American
Prep Time 20 minutes
Cook Time 40 minutes
Total Time 1 hour
Servings 12 servings
Calories 731kcal
Author John Kanell

Equipment

  • 9x13" cake pan
  • Electric mixer
  • Mixing Bowls

Ingredients

For the Cake:

  • 1 cup water (240 mL)
  • ½ cup unsalted butter (113g)
  • ¾ cup creamy peanut butter (198g)
  • 2 cups all-purpose flour (240g)
  • 2 cups granulated sugar (400g)
  • 1 teaspoon baking soda
  • ½ teaspoon salt
  • ½ cup milk (120mL)
  • 2 large eggs
  • 1 teaspoon vanilla extract

For the Peanut Butter Frosting:

  • 1 cup unsalted butter softened (226g)
  • 1 cup creamy peanut butter (264g)
  • 2 teaspoons vanilla extract
  • 2 cups confectioners’ sugar (240g)

Instructions

For the Cake:

  • Preheat the oven to 350°F. Spray a 9x13-inch cake pan with baking spray.
  • In a small saucepan, bring water, butter, and peanut butter to a simmer over medium heat, whisking constantly, until melted and smooth, about 3 minutes.
  • In a large bowl, whisk together the flour, sugar, baking soda, and salt. Add the milk, eggs, and vanilla. Beat with an electric mixer on medium speed until combined, about 1 minute. Beat in the peanut butter mixture until smooth. Pour into the prepared pan and spread into an even layer.
  • Bake for 40 minutes or until a wooden pick inserted in the center comes out clean. Let cool completely on a wire rack.

For the Peanut Butter Frosting:

  • In a large bowl, beat the butter and peanut butter with an electric mixer on medium-high speed until smooth and fluffy, about 2 to 3 minutes. Beat in the vanilla until just combined.
  • Gradually add the sugar while beating until smooth. Once incorporated, increase the speed to high, and beat until fluffy, about 1 minute. Spread the frosting over the cooled cake. The cake can be covered and stored at room temperature for up to 5 days.

Video

Notes

  • I highly recommend using a scale to measure your flour. However, if you don’t have a scale, be sure to fluff your flour with a spoon and then spoon it into your cups before leveling it off with a knife. This method is the best way to measure flour without overpacking the measuring cup, leading to a heavy peanut butter flavored cake.
  • Tap the cake pan on the counter a few times to pop any air bubbles and level out the batter in the pan for an even bake.
  • Careful not to overmix the batter, or you’ll overdevelop the gluten, and you’ll end up with a tough cake.
  • For a fun topping idea, try garnishing with some chopped roasted peanuts, Reese’s chocolate, or a chocolate ganache.
  • For the eggs to easily incorporate evenly into your batter without overmixing, bring them to room temperature beforehand. If you forgot to take your eggs out of the fridge ahead of time, you could quickly bring them to room temperature by placing them in a large bowl and covering them with warm tap water for 5 minutes.
  • An offset spatula is perfect for frosting the cake.
  • I like using real vanilla extract over artificial extract for the best flavor.

Nutrition

Serving: 1piece | Calories: 731kcal | Carbohydrates: 78g | Protein: 12g | Fat: 44g | Saturated Fat: 19g | Polyunsaturated Fat: 6g | Monounsaturated Fat: 16g | Trans Fat: 1g | Cholesterol: 93mg | Sodium: 371mg | Potassium: 271mg | Fiber: 2g | Sugar: 57g | Vitamin A: 771IU | Calcium: 47mg | Iron: 2mg