Perfect-For-Picnics Peanut Butter Sheet Cake

For the cake:

  • 2 cups all-purpose flour
  • 2 cups sugar
  • 1 1/2 teaspoons baking powder
  • 1/2 cup creamy peanut butter (I used Peter Pan brand)
  • 2 sticks (1 cup) salted butter
  • 1 cup hot water
  • 1/2 cup milk (I used 1% milk)
  • 2 large eggs, beaten
  • 1 1/4 teaspoons pure vanilla extract

For the icing:

  • 1 stick (1/2 cup) unsalted butter
  • 1/4 cup creamy peanut butter
  • 1/3 cup plus 2 teaspoons milk
  • 1/2 teaspoon pure vanilla extract
  • 4 - 5 cups powdered sugar, sifted (yes, it's important you really sift it to prevent lumpy icing!)

1.  Prepare your baking sheet with non-stick cooking spray and a large sheet of parchment paper and set it aside. Preheat the oven to 350°.

2.Combine the flour, sugar, baking powder in a large mixing bowl. Mix the dry ingredients well and set the bowl aside.

3. In a medium-size sauce pan, combine the butter and peanut butter in a sauce pan and melt over medium heat. Once the butters are melted add the hot water and stir well. Remove from the heat and let it cool down for just a minute or two. 

4. Pour the hot butter mixture over the flour mixture and mix it well with a wooden spoon until the ingredients are just combined. (don't over mix it, be gentle)

5. Pour in the beaten eggs, milk and vanilla. Mix until the batter is just combined.

6. Pour the batter onto the prepared baking sheet and spread it out as evenly as possible. Bake for 20 minutes or until a toothpick inserted in the center of the cake comes out clean. While the cake is baking, prepare the peanut butter icing.

7. For the icing, combine the butter and peanut butter in a saucepan over medium heat. Add the milk and bring just to a boil and turn off the heat. Add in the vanilla extract. Add the sifted powdered sugar, one cup at a time stirring with a wooden spoon or a whisk. Icing should be a medium-thick, glue-like consistency when ready. Cover the pan (or bowl if you transferred your icing, like I did) with plastic wrap or aluminum foil until it is time to use it otherwise it will start to dry in the bowl.  

8. Once cake is done, set baking sheet on a cooling rack and allow it to cool for 15 minutes. Pour your icing over the warm cake. Spread it out evenly and then allow it to cool completely.

9.  Serve and enjoy!

Recipe from A Little Fish in the Kitchen blog at All content is owned by Marcelle G. Bolton. Please contact the author for permission to republish.