Old-Fashioned Peanut Butter Cake

This cake is a Peanut Butter Lover’s Heaven!  Moist and tender Peanut Butter Cake, smothered in warm peanut butter frosting and topped with roasted peanuts!  So.Dang.Delish!

From The View From Great Island, this cake is bound to become a favorite in your house – so easy to make, no need to get out even a hand-mixer, just stir and bake! Not to mention the intense Peanutty Flavor! The peanut butter cake of your dreams!

I adapted the recipe by using all-natural peanut butter, just peanuts and salt.  If you decide to use all-natural, just be sure it is stirred together as well as you can so it doesn’t separate during the bake.

Just bake it in a 13×9, cook the frosting and pour that magical stuff over the cake!  Serve warm, at room temperature, or cold – all super yummy! If there are any leftovers, they keep nicely in the fridge (well-wrapped) for several days, at least.

  • Author: Laura



For the Cake:

  • 2 c (240g) AP Flour
  • 2 c (400g) Granulated Sugar
  • 1 tsp Baking Soda
  • 1 tsp Salt
  • 1 Stick (113 g or 1/2 c) Unsalted Butter (or reduce salt to 3/4 tsp.)
  • 1 c Water
  • 1/2 c (125 g) Smooth Peanut Butter, any type
  • 1/2 c (112 g) Vegetable Oil
  • 2 Lg eggs, room temp
  • 1/2 c Buttermilk, room temp
  • 1 tsp Vanilla Extract

For the Frosting:

  • 1 Stick (113 g or 1/2 c) Butter
  • 1/2 c (125 g) Smooth Peanut Butter (any type)
  • 6 T Buttermilk, plus a bit extra,  if needed
  • 1 tsp Vanilla Extract
  • 3 c (340 g) Confectioner’s Sugar, sifted


  • 1/41/2 c Roasted Peanuts


Make the Cake

  1. Preheat oven to 350F (or 325 F for Convection).  Spray a 9×13 pan. 
  2. In a Large bowl, whisk together the flour, sugar, baking soda and salt. Set aside.
  3. In a small saucepan, heat the butter and water.  When it comes to a boil, take it off the heat and whisk in the peanut butter and oil until smooth.  It should be pretty thin. Let the pan cool several minutes and whisk in the eggs, buttermilk and vanilla until well-blended.
  4. Pour the wet ingredients into the dry ingredients, and whisk until just combined.
  5. Pour the batter into the prepared 9×13 and bake 40-45 mins (mine took 40 mins), until a toothpick inserted into the center comes out clean. Set the cake over a cooling rack while you prepare the frosting.

Make the Frosting

  1. In a saucepan, heat the butter, peanut butter and buttermilk and bring to a full boil. Remove the pan from the heat. Beat in the vanilla and confectioner’s sugar (a cup at a time). Beat until smooth following each cup of sugar. It’s nice to reheat the whole batch a bit before pouring over the cake, because the frosting sets up on the cake pretty quickly. Add extra buttermilk a Tablespoon at a time if it becomes too stiff to pour.
  2. Pour the hot frosting over the warm cake and spread evenly. 
  3. Garnish with roasted peanuts.


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