Peanut Butter Fudge Iced Brownies
One bite of these Peanut Butter Fudge Iced Brownies is all it takes to understand why they’ve been a longtime favorite! The old-fashioned boiled peanut butter icing creates a thick, candy-like layer over fudgy brownies for a decadent treat that tastes like it came straight from grandma’s kitchen. Make it once and it’ll be in your regular rotation!

Brownies + Peanut Butter Fudge Icing = A Match Made in Heaven
This icing has been a family staple since I first shared it on Southern Plate back in 2008… and honestly, I’ve lost count of how many of you have made it since!
We’ve always done it over yellow cake, but the day I poured it over brownies, everything changed. A dense, fudgy brownie is the perfect base for this old-fashioned boiled peanut butter icing.
These peanut butter fudge iced brownies perfectly combine rich chocolate with a thick, candy-like peanut butter topping. It’s a combination that feels like it was always meant to be, and once you try it, you’ll wonder why you ever had brownies any other way!
Ingredients
- Boxed brownie mix
- Sugar
- Milk
- Shortening
- Margarine
- Salt
- Vanilla
- Creamy peanut butter
Frequently Asked Questions
I usually get Kroger or some other generic brand – nothin’ fancy here! I’d go for whatever is cheapest where you shop because I’ve never met a brownie mix I didn’t like 😊.
You don’t have to use two boxes of mix, one is fine and you get to taste more of the icing!
To make your brownies thicker, use two boxes of brownie mix. This is how I like to do it! If you do this, you need to cut your oven temperature down to 325°F and add about 15 minutes to the baking process.
Of course! You can use your own recipe or I recommend my friend Susan Spencer’s Grandmothers recipe for Blue Ribbon Brownies. The peanut butter icing will take on the star of the show so go with whatever you prefer and what you have time for, but as for me and my house, we will make them from a mix today.
How to Make Peanut Butter Fudge Iced Brownies
Step 1: Preheat the Oven
Preheat your oven to 350°F and spray a 9×13 or 8×8 inch baking pan.

Tip: If making an 8×8 inch pan of brownies, I’d still use this same amount of icing and just let it be thicker.
Step 2: Mix & Bake Your Brownies
First, you’ll need to whip up some brownies. Just follow the directions on the package. Once they’re baked, let them cool completely before you start on the icing.

Step 3: Make the Icing
Place your milk, sugar, shortening, margarine, and salt in a good sauce pot and put this over medium heat.


Stir constantly while you wait on all of it to melt and come to a boil. Then stop and let it boil on its own (no stirring) for 2 minutes.

Step 4: Beat it, Spread it, & Serve
Remove from heat and stir in your vanilla and peanut butter.


Beat that until it’s nice and smooth, then spread it over your brownies as fast as you can.


Now allow for the icing to cool and set on your brownies. You can occupy yourself during this time by licking the sauce pot clean once it cools enough to let you 😉.
Serve & enjoy!
How to Store Peanut Butter Fudge Iced Brownies
Store your delicious Peanut Butter Fudge Iced Brownies in an airtight container at room temperature for up to 3 days. Alternatively, you can store them in the refrigerator for up to 5 days.

Ingredients
- 1 box brownie mix prepared according to package directions*
- 1-½ cups sugar
- 7 tablespoons milk
- 2 tablespoons shortening
- 2 tablespoons margarine
- ¼ teaspoon salt
- 1 teaspoon vanilla
- ½ cup creamy peanut butter
Instructions
- Prepare brownies according to package directions and allow to cool completely before beginning icing.
For the Icing
- In a heavy saucepot, combine the sugar, milk, shortening, margarine, and salt. Bring to a rolling boil while stirring constantly.
- Once it reaches a rolling boil, stop stirring and let it boil for two minutes or until it reaches the soft ball stage (I don’t use a thermometer, I just let it boil for two minutes).
- Remove from heat and quickly stir in the vanilla and peanut butter. Beat until smooth and quickly spread over the brownies.

These look fabulous! I can’t wait to try them.
I hope you get the chance to soon Jan!
Christy…dying to try this today for hubby. Car in shop, no shortening in the house but have everything else. Will it be missed? Can I double up on the margarine? Wondered if it helped with the thickening process? Opinion please and they sound WONDERFUL…..Carol
Yes Christy-I was also wondering if you could leave the shortening out? Sounds delicious!
Yes i would use it to ice a Texas sheet cake yummo
ohhh, that sounds good!
my mom uses this frosting on top of rice krispy treats…a family favorite!!!! this does sound yummy will be on my Christmas treats list thanks for the recipe!
All I can say is YUMMMMMMY! Easy to make and delicious.
I am so glad to hear that you liked them Lisa!! They are always a favorite around here and go quickly.
I made this icing on the yellow cake. I used margarine, shortening, brown sugar, and skim milk. I timed it to boil exactly 2 minutes, and it was very runny. Most of it ran down the sides and under the cake instead of staying on top of it. What did I do wrong?
Amazing taste though, even though we’re scraping the icing off the sides and bottom of the pan!
First off, I’m so sorry this didn’t turn out perfect for you! BUT I’m glad it tasted good! You seem to have my attitude towards things, if we can still eat it, we’re gonna be grateful for it! Even if we can’t, we’ll still find some reason to be thankful! lol
I have never used skim milk in making this and all of the other ingredients are just how I always do them, so I’m thinking the skim milk has to be the culprit here. If you don’t normally stock whole milk, a good way to get around changing your habits would be to keep evaporated milk in a can on hand and that should work just fine. I hope you try it again and I am so sorry it didn’t turn out!
Gratefully,
Christy
I wondered about the skim milk too but wasn’t sure. I should be just stirring it briefly to cool it slightly before pouring on the cake – right? Not getting out my mixer and beating it into submission? How thick should it be before I pour it on the cake?
Thanks for your help! I’m eating way too much of this cake the last couple of days.
I made these brownies with pbf icing a few days ago and they are delicious! However, I did have a question…..my icing ended up kind of dry and crumbly and didn’t stick to the brownies at all. When I tried to cut the brownies (with icing on them) it ended up being a bit of a mess. Tasted great yes – looked great – not so much. Any idea what I might have done wrong to the icing to make it dry and crumbly? Thanks very much!