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!
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
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
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.
Immediately pour it onto the baked and cooled cake.
Allow it to cool before serving.
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?
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.
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:
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- 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:
Italian Cream Cake with Pecan Cream Cheese Icing
7-Minute Frosting (Foolproof Recipe)
Vegan Sweet Potato Cake With Maple Cashew Icing
Cappuccino Cake With Cappuccino Buttercream Frosting
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
This post was originally published in July of 2008. I updated the photos in August 2019.
Do you have a caramel version – like penuche? My mouth is watering just thinking about your variations of this yummy icing.
One of my favorite cakes and can’t wait to share it with my grand children. I so enjoyed your story about your family, thanks for sharing! I debbie
Thank you so much for sharing this recipe. My mom passed away 2 years ago and unfortunately I had not written down her peanut butter frosting recipe. I ran across yours and was thrilled. It’s exactly like hers. My mom’s favorite time of year was Christmas and you had to have peanut butter cake. This time of year I miss her more than usual, so being able to make this cake feels like I have her a little closer, if you understand what I’m saying. Again thank you. Merry Christmas. I’m gonna have a slice of peanut butter cake.
I understand completely Kathy. I hope you have a Merry Christmas and enjoy the cake!!
My husband loves this peanut butter cake. His mom made it all the time. So I’m going to make it but in a sheet cake pan with the candy on top. Also I’m going to use a yellow cake mix. Pray it turns out ok!! Thanks for sharing this.!
How fun, he is going to be so excited to see a favorite and I just know it will turn out great but I will say a prayer just in case 😉
Yep, made me cry. What a special story, thank you for sharing! My husband asked me to make him an old fashioned peanut butter cake like he had as a kid and I knew this was the recipe. God bless.
I didn’t mean to make you cry Dayna, I hope it was a good kind of cry though! I hope this is the one, you will have to let me know after you get a chance to make it for him. May God Bless you as well!!
Thank you so much for posting this recipe. My aunt used to make this cake and icing from scratch when I was 10 years old. I remember when I used to sit and wait for her to finish icing the cake. The smell of the icing simmering would hypnotize me! I’ve attempted to make this icing but couldn’t remember all the ingredients. She passed about 15 years ago so I couldn’t ask her how to make this icing!! This recipe is the closest to her peanut butter icing so once again thanks for sharing.
I hope you enjoy a big piece in her honor along with the walk down memory lane!!
Help! I attempt to make this icing and it hardens IMMEDIATELY when I add the PB and instantly clumps up…so much so that it clogs up my wire wisk with a cement-like consistency. I do try to put back on heat to loosen it up, and I have added milk to it, but the icing still stays sooo clumpy! My daughter wouldn’t eat it because it was so clumpy that she thought I used crunchy PB. What can I do to get the smooth icing? Thank you!
Hey CarusoneGirl! First of all, I have to commend you for not giving up! It is a rare thing these days to see folks keep working with a recipe if it doesn’t turn out perfect the first time. You chose a great recipe to stick with, too! I’ve been making this one as long as I have been cooking so I’ve had times where it turned out not so hot as well. Sounds to me (because I have been there) that it is overcooked. Different stoves and different temperatures just can’t be avoided. I feel confident that if you cut the boiling time down to one minute, it will work just fine. Now keep in mind that it will still be very thick but pourable and it will harden after it cools completely. So you may be thinking “I didn’t cook it enough!” but as long as you bring it to a boil and then start timing one minute from there it should turn out fine.
Having said that, from time to time I still have a batch that isn’t “perfect” but we find that it is absolutely delicious anyway 🙂
My batch was too runny. It never hardend. I let it boil for 2 minutes then put it in my Kitchen Aid mixer to mix in the peanut butter. It was too runny for my cup cakes. Too bad I hadn’t made a sheet cake. It would’ve been good as a peanutbutter poke cake 😉
Hey! I’m sorry it didn’t work out. It may be the environment where you are requires more cooking time. The best way to make sure is use a thermometer next time you make it and get the temp to 245 degrees and see how long that takes to happen. There are too many variables to have another sure fire way to know. My friend, Jyl, and another friend make the same boiled icing but live in different parts of the country, one of them has to boil theirs for double the time.
I would never ever ever recommend this recipe for cupcakes though, if you can help it. I don’t think anyone born after 1945 can ice a cake or cupcake with a boiled icing before it hardens 😉