Old-Fashioned Peanut Butter Icing

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Transform an ordinary yellow cake with this delicious sweet and nutty old-fashioned peanut butter icing recipe. It’s a must-make for peanut butter fans!

Hero image for old-fashioned peanut butter icing.

Today, I’m sharing a recipe with a big old root system behind it: yellow cake with old-fashioned peanut butter icing. The cake we’re going to use is just a boxed mix because spoiler: it’s not the cake that is important here, it’s the icing. This is my grandmother’s old-fashioned peanut butter icing recipe to be exact and it will forever remind me of my great aunt, Red.

Now, most old-fashioned icing recipes are of the boiled icing variety. If this technique scares you, don’t worry, I’ve included lots of tips for success below to make sure you nail it every time. Trust me, when you get it right and give it a taste, you’ll want to make it again and again. Who can resist a thick layer of sweet yet nutty peanut butter icing on their favorite cake? Certainly not me! The best part of boiled icing is that you pour the hot icing onto the cooled cake and it hardens like fudge… YUM!

To make my peanut butter frosting, you’ll need creamy peanut butter (of course), as well as icing essentials like granulated sugar, vanilla, milk, shortening, and butter. So grab those ingredients and get ready, because I just know you’re going to love this old-fashioned peanut butter icing recipe as much as I do! And if you don’t love peanut butter check out Boiled Chocolate Icing 

Ingredients for Old-Fashioned Peanut Butter Icing.

Recipe Ingredients

  • Sugar
  • Shortening (I use coconut oil these days)
  • Peanut butter
  • Milk
  • Vanilla extract 
  • Unsalted butter

Helpful Kitchen Tools

How To Make Old-Fashioned Peanut Butter Icing

Add ingredients to a saucepot (except vanilla and PB) and bring to a boil.

In a large saucepot, combine sugar, milk, shortening, margarine, and salt.

Bring to a rolling boil over medium-high heat, stirring constantly to prevent scorching.

Once it reaches a boil, let it boil for two to three minutes without stirring.

Remove from heat and immediately stir in the vanilla and peanut butter.

Beat until icing is smooth and starts to lose its shine. 

Pouring icing onto cake.

Immediately pour it onto the baked and cooled cake. 

Allow it to cool before serving.

Allow it to cool before serving.

Cutting slices of yellow cake.

Look at that nice layer of peanut butter fudge icing! 

Can you see why yellow cake with old-fashioned peanut butter icing is such a special cake? 

Piece Of Yellow Cake with Old Fashioned Peanut Butter Icing

This is a sight to behold.

Guess what? It seems like it was a gift from above, but as a precious reminder of my past and its connection to the future, this is my daughter’s favorite cake. 

Take A Bite! Yellow Cake with Old Fashioned Peanut Butter Icing.

Now excuse me while I dig into this delicious slice of yellow cake!

Storage

Store leftover cake in an airtight container in the fridge for up to 1 week.

Recipe Notes

Here are my tips for success when it comes to boiled peanut butter icing:

    • The boiling of the icing is the most critical step. Make sure it comes to a rolling boil and then stay right there, timing it. I suggest adding one minute to be on the safe side but don’t go over this as the icing will scorch. 
    • You absolutely must have your cake done and ready the moment the icing is done. 
    • Once your icing is finished, remove it from the heat and use a wire whisk to quickly stir in the peanut butter and vanilla until the icing thickens a bit and starts to lose some of its shine. It should still be pourable. 
    • Don’t try to spread the icing once you’ve poured it. Instead, pour it evenly over the cake so that no spreading is needed.
    • Most importantly, unless you lived through the Great Depression, I strongly encourage you not to use this on anything other than a sheet cake. Only those who have the crown of wisdom that comes through age and hardship can ice a layer cake with this. 
  • If you want more peanut butter flavor, sprinkle the cake with roasted peanuts or crushed nuts.
  • Natural peanut butter doesn’t work as well as regular peanut butter in this recipe.
  • For creamier icing, you can substitute the milk for buttermilk.

Recipe FAQs

What other cakes work well with old-fashioned peanut butter icing?

You can use any kind of boxed cake mixes, such as vanilla cake, angel food cake, golden cake, white cake, or even chocolate cake (which will suit Reese’s Peanut Butter Cup fans). But if you’re looking for a homemade cake recipe, Aunt Sue’s easy pound cake would be perfect with this peanut butter icing.

Check out these other irresistible icing recipes:

Boiled Chocolate Icing

Italian Cream Cake with Pecan Cream Cheese Icing

7-Minute Frosting (Foolproof Recipe)

Vegan Sweet Potato Cake With Maple Cashew Icing

Creamy Chocolate Frosting

Cappuccino Cake With Cappuccino Buttercream Frosting

Old-Fashioned Peanut Butter Icing

Transform an ordinary yellow cake with this delicious sweet and nutty old-fashioned peanut butter icing recipe.
Prep Time: 20 minutes
Cook Time: 40 minutes
Total Time: 1 hour
Course: Dessert
Cuisine: American
Keyword: cake, icing, peanutbutter
Servings: 0
Calories: 318kcal

Ingredients

  • 1 Duncan Hines yellow cake mix made according to package directions and cooled
  • 1.5 cups sugar
  • 7 tablespoons whole milk
  • 2 tablespoons shortening
  • 2 tablespoons unsalted butter
  • 1/4 teaspoon salt
  • 1 teaspoon vanilla extract
  • 1/2 cup creamy peanut butter

Instructions

  • Prepare cake mix in a 9x13 baking dish as directed on the package. Allow it to cool.
    1 Duncan Hines yellow cake mix
  • In a large saucepot, combine sugar, milk, shortening, butter, and salt. Bring to a rolling boil over medium-high heat, stirring constantly to prevent scorching.
    1.5 cups sugar, 7 tablespoons whole milk, 2 tablespoons shortening, 2 tablespoons unsalted butter, 1/4 teaspoon salt
  • Once it reaches a boil, let it boil for two to three minutes without stirring.
  • Remove from heat and immediately stir in vanilla and peanut butter. Beat until icing is smooth and starts to lose its shine. Immediately pour it onto the cake and allow it to cool before serving.
    1 teaspoon vanilla extract, 1/2 cup creamy peanut butter

Nutrition

Calories: 318kcal
Tried this recipe?Mention @southernplate or tag #southernplate!

This post was originally published in July of 2008. I updated the photos in August 2019.

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160 Comments

  1. WHAT???? Authentic Southern Buttermilk Biscuits??????? Where was I? I missed that recipe. Can you direct me to where I can find it? 🙂

    I was reading the posts about the delicious looking PB Bars and frosting and saw where a comment was made about the buttermilk biscuits. Couldn’t resist asking for that recipe.

    I join the others wanting the Buttercream Peanut Butter Frosting. So, Christy, If Pinky shares that with you, would you mind to post it in one of your blogs (that you email out) for all of us????? Pretty Please with sugar on top????

  2. Oh my goodness, I made this cake today for my birthday and the peanut butter frosting is awesome. I can’t stop eating it. This is a keeper and will be added to the receipe book I am creating for my family (none of whom can cook a lick). thanks Christy.
    Oh, it’s 59 in case you were wondering.

      1. My Granny made this cake for my Daddy’s birthday each year, and one day she handed me the spoon and said you make it. Well I did but over the years put my own spin on it for a smoother, creamy frosting. I changed my recipe to powdered sugar, peanut butter, vanilla and canned milk. It takes only a few minutes and it doesn’t hardened like regular sugar. No butter or Crisco are needed. It’s easier to spoon the warm frosting over a bundt style cake.** Our family enjoyed three layer peanut butter cakes, and we always got our desserts first at a gathering, so you know we aren’t playing around!
        @Christy- Just curious to find out your thoughts.

  3. So it’s been a week since I made the chocolate cake with the icing, and I’m STILL thinking about how good that icing was. I really want to try making a yellow cake with mini chocolate chips in the batter, then PB icing on top. If only I could come up with an excuse to make another cake so soon…

  4. Christy, I love the story behind this peanut butter icing! My soon to be in-laws (2 months until the wedding!) came up this weekend and, of course, that’s a great reason to bake a cake. They love chocolate so I tried out this recipe for “Too Much Chocolate Cake”: http://allrecipes.com/Recipe/Too-Much-Chocolate-Cake/Detail.aspx?prop31=7

    and topped it with the peanut butter icing. I ended up stirring it the whole time because I was afraid of it burning, and boiled it for a tad over 2 minutes. I was afraid it may not set up and actually waited a couple minutes before pouring it on the cake, but it turned out just fine. And what a hit the cake was! Everyone really enjoyed it, which made me super happy. The cake and icing combo almost reminded me of homemade snack cakes. I beg you to try that chocolate cake with the peanut butter icing, I think it’s right up your alley. I’ll have to make the yellow cake to go with the icing sometime, too (don’t tell them, but I actually prefer yellow cake to chocolate). My fiance asked if I could possibly make a chocolate version of the icing and he was pleased to hear that you have one on your blog 🙂

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