Whip up soft chocolate whoopie pies with the help of a cake mix, then fill them with a tasty peanut butter marshmallow filling for an extra memorable treat!

Homemade chocolate peanut butter whoopie pies are the perfect mix of cookie, cake and frosting. This recipe uses the shortcut of a cake mix, so they are super simple to make.
The filling has bold peanut butter flavor with the marshmallow undertones you would expect in a classic whoopie pie. The end result is a fun hand held treat that is sure to wow.
Have you ever had a whoopie pie? The soft cake-like cookies sandwich a creamy marshmallow filling for a tasty dessert sandwich.
They are the official state treat of Maine and a Pennsylvania Amish tradition. For good reason too, they are super delicious.

Each bite is like a mash up of some of our favorite desserts. They are part cake, part cookie and of course that sweet filling draws you in.
Luckily with the help of a cake mix, you can whip up a batch with almost no effort at all. Plus that make changing out the flavor profile super simple.
I will highlight some tasty whoopie pie flavor ideas below to get your creative juices flowing. If you try some, let me know how it goes.
But if you are a chocolate and peanut butter fan, you have to start with this recipe as written. They are super delicious and the hefty amount of peanut butter helps keep these whoopie pies from tasting too sweet.

Tips for Baking Cake Mix Whoopie Pies
Because you start with a cake mix, the batter comes together really quickly. Just make sure your butter is softened so everything incorporates nicely.
The batter should be like a thick cake batter or slightly loose cookie dough. It’s a little bit sticky but should be able to mostly hold its shape.

Using a cookie scoop is a great way to evenly portion the dough while also giving them a nice round shape. I used a medium cookie scoop for these and the resulting whoopie pies were relatively large.
You can use a small cookie scoop to get twice as many smaller treats. Which is better will totally depend on how you plan to serve them.
To get the best thick, soft, cake like cookie you will want to refrigerate the scoops of dough for about a half hour. That will give you nice rounded domes and cakey interiors.
Let them cool completely and add your filling. It really is that easy!

The Peanut Butter Fluffernutter Filling
Whoopie pies traditionally have a marshmallow-y filling, so I wanted to keep the tradition alive in these. But of course I wanted to do something a little different as well.
Adding peanut butter was a perfect solution! The peanut butter brings that little bit of salty savory and pairs wonderfully with the chocolate.

If peanut butter isn’t your jam, marshmallow fluff buttercream would be a fabulous option. Or use a simple vanilla American buttercream.
Once the cookies have cooled, you can spread, pipe or scoop the filling on on and top it with another. Frosting fanatics, feel free to be generous with that filling!
More Easy Whoopie Pie Flavor Combination Ideas
You can easily use this base recipe and switch out the cake mix you use to make an endless variety of whoopie pie flavor combinations. In fact, it would be fun to do a display of different types as a fun dessert spread at a party.
If you decide to do more than one flavor, just be sure to make the smaller versions. People are definitely going to want to try more than one!

Lemon lovers can use a lemon cake mix to make fun citrusy whoopie pies. Some lemon sweetened condensed milk buttercream would be a fabulous filling. Or make lemon blueberry whoopie pies for an extra summery treat!
Use funfetti cake mix and fluffy sweetened condensed milk buttercream for birthday whoopie pies.
Or use a butter recipe vanilla cake mix and chocolate sweetened condensed milk buttercream for an inside out whoopie pie.
A red velvet, carrot cake or spice cake mix would pair wonderfully with decorator’s cream cheese frosting.
See the possibilities really are endless!

How do I store homemade whoopie pies?
These whoopie pies can be stored at room temperature for a couple of days. You can refrigerate them for up to a week or freeze them for a few months. However, they will have the best texture when enjoyed at room temperature.
More Cookie Recipes
Maple cinnamon cookies are kissed with the warmth of maple and brown sugar and a hint of cinnamon. They are big and chewy and oh so good!
Super soft sugar cookie bars topped with a fluffy layer buttercream are a fun and easy treat. They are so much quicker to make than individual cookies and taste great!
Make simple chocolate spritz cookies extraordinary by sandwiching a layer of rich ganache style frosting between them.
Chewy brown sugary blondies loaded with chocolate chunks, caramel undertones and topped with M&Ms. This big batch of bars is perfect for a party, carry-in or just because.
Did you make this great recipe? Please leave a review in the recipe card below!

Easy Chocolate Whoopie Pies with Peanut Butter Marshmallow Filling
Ingredients
Cake Mix Whoopie Pies
- 15.25 oz chocolate cake mix
- ½ cup butter softened
- 3 large eggs
- ¼ cup sour cream
Peanut Butter Marshmallow Filling
- 1½ cups creamy peanut butter
- 7 oz marshmallow fluff
- 1 cup powdered sugar
- 1 Tablespoons milk
Instructions
Whoopie Pies
- Line 2 baking sheets with parchment paper or a silicone mat and set aside.
- Beat butter until smooth and creamy.
- Add cake mix, eggs and sour cream. Mix until just combined.
- Use medium cookie scoop to put 12 cookies on each baking tray, leaving at least 2 inches between each scoop of dough.
- Chill scoops for at least 30 minutes.
- Preheat oven to 350° F and bake chilled cookie scoops for 11-12 minutes.
- Cool on the baking sheet for 2 minutes, then move to a wire rack to cool completely.
Filling
- Mix together peanut butter and marshmallow fluff until combined.
- Stir in powdered sugar.
- Add enough milk to get it to your desired consistency.
- Pipe, spread or put a scoop of frosting on half of the whoopie pies. Top with a second whoopie pie to form a sandwich.
- Store your whoopie pies in an airtight container on the counter or in the refrigerator for up to 5 days. For longer storage, wrap individually and freeze.
Notes
Video
Nutrition

Sue
Saturday 5th of August 2023
Yummy whoopie pies! 😋. They came out perfect but I will definitely do the smaller ones next time! 😁 BTW, I used crunchy peanut butter and increased the amount by 1/4 cup to make up for the difference the pieces of peanuts made.
Carlee
Saturday 5th of August 2023
I'll bet the crunchy peanut butter added a nice bit of texture. I am glad you liked them!
Julie
Wednesday 31st of August 2022
I made this recipe according to directions and the first batch of cakes spread out into each other, even after refrigerating for 30 minutes. The second tray kept its shape but they are not very sturdy. The peanut butter filling is greasy and broken. Not creamy enough to pipe.
Carlee
Thursday 1st of September 2022
I'm really sorry that happened to you. Were you using standard butter and peanut butter?
Kathy
Saturday 2nd of July 2022
Can you freeze these? If not how long will they keep?
Carlee
Saturday 2nd of July 2022
You can freeze them for up to three months. I would freeze them for a couple of hours on a sheet pan before wrapping them and putting them back in the freezer. Then you may want to unwrap them to defrost them as well, otherwise they might stick to the plastic wrap as they thaw.
jenny
Wednesday 23rd of March 2022
DO NOT CHILL these, it flattens them. There is no need, just scoop and toss in oven. This recipe could use some dramatic improvement. As is, waste of ingrediants.
Carlee
Sunday 21st of May 2023
Actually, having the butter cold when you put them in the oven allows the shape to set before the butter melts. Putting room temperature butter/dough into a hot oven allows the butter to melt and the batter to spread before they have a chance to set.
nikia Isit
Friday 10th of December 2021
Can you substitute anything for sour cream
Carlee
Friday 10th of December 2021
Greek yogurt would be a good substitute if you prefer.