Perfect Peanut Butter Italian Buttercream

Creamy, smooth, buttery, and perfectly sweet - Peanut Butter Italian Buttercream will quickly become one of your favorite buttercreams in existence.

 I'm THAT girl. And by "that," I mean.. I am frequently caught in the kitchen eating peanut butter by the spoonful. I picked up that trait from my mom. I just love it. I can't get enough of it. 

If I can't decide on what to eat, I will just grab the jar of peanut butter. Sometimes I will grab something to eat with it like a sliced apple, gluten free pretzels, crackers, a rice cake, or whatever is closest. But, most times, I just grab a spoon and go to town.

So, obviously I love things that are also made with peanut butter. I love peanut butter rice crispy treats, peanut butter fudge, peanut butter ice cream, and literally... anything you could make. I am dead serious about this. I just love it. 

When I was preparing to make a cake for the judges on Halloween Wars Episode 7 - in the SEMI FINALS of Season 12, I decided to put my personal spin and favorite flavors into their cake. 

We were tasked to use elements from the sea; so I chose to use both sea salt and dulse! After researching, I discovered that a lot of people will fry dulse until it is crispy and use it as a vegan bacon substitute. I thought that would be the perfect addition to one of my favorite cake combos. 

Chocolate. Peanut Butter. Salted Caramel. Crunchy Peanuts. and Bacon ... except, just no bacon. Only seaweed.. deep fried and covered in chocolate. Plus, add some ginger in the caramel for some more depth and a hint of spice. It was divine.

Eddie Jackson even went to the extent of saying, "Hannah, I'm going to be honest with you - this is probably the best cake I've had all season. You've got some things going on inside this cake that I think are absolutely amazing. This is a gluten free cake, and you CAN'T TELL ME this is gluten free... I wouldn't change a thing about it."

If you watched the episode, you would have seen how shocked and stunned I was. I have never been that speechless before. All of the episodes are on the streaming service, Discovery+, to be rewatched. Go check it out!

Chocolate and peanut butter will forever be one of my favorite flavor combinations. However, this icing is fabulous on just about any flavor of cake. I love it with a classic vanilla cake, as well. Oh man, it would be fabulous on a banana cake, even a cinnamon spice cake, or something like that. Slathering this over brownies, brown butter blondies, or sugar cookies would also be heavenly. However, I have a soft spot for the original chocolate cake goodness.

This buttercream is once again made with an Italian Meringue and softened butter. It is light, buttery, airy, and dreamy. 

Once you put in the effort to make an Italian Meringue, you will never return to the classic stuff. It takes a little bit of practice and multitasking, but it is well worth it. I also recommend investing in a nice thermometer to make this process easier. I love the Thermoworks Chef Alarm, and it got me through culinary school. Love it! (Not sponsored, I just love it.) 

For extra tips and tricks on how to make an Italian Meringue Buttercream - check out my Classic Vanilla Bean Italian Buttercream recipe here

Other recipes similar to this one:

- The Best Brandy Italian Buttercream

- Milk Chocolate French Buttercream

- Traditional Vanilla Buttercream

Like I mentioned above, I used this buttercream on the Gluten Free Chocolate Cake with Seaweed that I presented to the judges, Aarti Sequeira, Shinmin Li, and Eddie Jackson on Episode 7 (THE SEMI FINALS!!) of Food Network's Halloween Wars - Season 12. They loved it, and absolutely could not get over the fact that it was gluten free. A killer compliment. Life complete. 

  Perfect Peanut Butter Italian Buttercream

              Prep Time: 10 mins
Cook Time: 10 mins
Total Time: 20 mins

                   Recipe Yield: 3 1/2 lbs ~ Enough to fill & cover 1x 3-layer 8" cake

                   Recipe by: Hannah Catherine - Rosemary Whisk


12 oz            Sugar #1

4 oz             Water

8 oz             Egg Whites, fresh (not from a carton)

4 oz             Sugar #2

2 lbs           Butter, softened

1 Tbsp        Vanilla Bean Paste

1/4 tsp        Salt

4-6 oz         Peanut Butter, creamy (not natural)


1. Wipe the inside of your stand mixer bowl and whisk attachment with a cut lemon. This helps to get rid of any lingering fat particles that might be present. Meringue hates fat. So, wipe the bowl out. You can also use a splash of white vinegar or bottled lemon juice.

2. Combine the #1, large portion of sugar and water in a small saucepan with a digital thermometer. 

3. Bring the sugar and water to a boil over medium-high heat. Just after you begin cooking the sugar, add the egg whites to the clean mixing bowl. Begin whipping on low until frothy, and slowly add the #2, smaller portion of sugar. 

4. When your sugar syrup has reached approximately 230F, raise your mixer to medium speed and whip the meringue until it reaches medium peaks. 

5. Once the sugar syrup has reached 239F (soft ball stage) - turn the speed of your mixer up to medium high and begin pouring the syrup in a steady stream towards the edge of the bowl. Add all the syrup and let the mixture whip until it cools down to about room temperature. This could take 7-10 minutes. 

6. Once the meringue has cooled to room temperature, begin adding the softened butter. Once you begin adding the butter, add it all quickly to ensure the butter incorporates before the meringue cools too much.

7. Let this whip until it is completely combined. This could take 3-4 minutes. If it separates, give the mixture time to cool down more and come back together. When in doubt, just keep whipping it.

If the butter remains in chunks - it means that the butter was too cold when it was put it in the meringue. So, continue to let it whip, while heating the outside of the bowl with a blowtorch. Only a few seconds at the time, whipping in between. or, just very gently heat it over a little warm water for a few seconds. Don't overheat - or, you'll have buttery soup on your hands. 

8. Add a little vanilla, salt, and the peanut butter - mix until incorporated. and, you're set. Taste to see if you want to add more peanut butter, but you're all ready to go!


- Buttercreams like Italian and French Buttercreams (like this Milk Chocolate French Buttercream, Vanilla Italian Buttercream, and Brandy Italian Buttercream) are very forgiving. They take practice to figure out the timing, but they are so worth the extra work. If it splits, usually it can always be fixed. If it is too cold and chunky, that can also be fixed. I have learned to always keep my blowtorch handy. It's one of my most used kitchen tools. 

- I have never tried making Italian buttercream with Natural Peanut Butter - the peanut butters made with only peanuts and salt, so I am not sure how it would work in this recipe. However, I am not sure that it would combine well with the meringue. Unless you're feeling brave and don't mind risking a possibly ruined buttercream, I suggest just sticking to the traditional creamy peanut butter that doesn't tend to separate. 

- This buttercream is the perfect compliment to the cake I made in Episode 7 of Food Network's Halloween Wars - Season 12. Check it out! Gluten Free Chocolate Cake Layers with Ginger Sea Salt Caramel, Roasted Peanuts, Fried & Chocolate Covered Dulse, and this magical peanut butter goodness. 

With love & buttercream,

Hannah Catherine

Made the recipe?
Mention @rosemarywhisk or tag #rosemarywhisk!