These Chocolate Peanut Butter Whoopie Pies are two moist chocolate cake cookies stuffed with peanut butter marshmallow filling. They are easy and made in one bowl with a whisk in 30 minutes.

Whoopie pies are just SO fun! They are so quick to whip up, are impressive to serve, and are absolutely delicious! Check out my Red Velvet Whoopie Pies for a classic pairing of red velvet cake and cream cheese frosting or these Oreo Whoopie Pies for a cookies and cream twist!
What Makes This Recipe Work
- These pay homage to the classic peanut butter cup, mixing chocolate and peanut butter in one treat
- 2 moist, fluffy, one-bowl chocolate cake cookies
- Peanut butter marshmallow whoopie pie filling
- Quick to make in 30 minutes with simple ingredients

Ingredients
- All Purpose Flour: All purpose flour creates moist, chewy, and fluffy chocolate cake pieces. However, make sure to measure flour properly. Read "Expert Tips" below for more information.
- Unsweetened Cocoa Powder: The chocolate flavor in these whoopie pies comes from cocoa powder. I use natural, but dutch processed should work too.
- Baking Soda & Baking Powder: These two leavening agents create light and domed cake cookies.
- Salt: Salt brings out sweetness and enhances flavor.
- Granulated Sugar & Light Brown Sugar: Both sugars add to sweetness, moisture, and structure.
- Egg: An egg at room temperature creates chewiness in these chocolate cake sandwiches.
- Vegetable Oil: Vegetable oil creates a moist cake that maintains moisture and flavor.
- Vanilla Extract: Pure vanilla extract rounds out the flavor.
- Buttermilk: Room temperature butter creates a tender cake crumb.
- Water: Hot water brings out the chocolate flavor and smooths out the batter.

Step by Step Process
STEP 1: Preheat your oven to 350 degrees Fahrenheit. Then, line a baking sheet with parchment paper, as doing so will allow the whoopie pies to come off of the pan cleanly.


STEP 2: In a medium bowl, use a wire whisk to stir your dry ingredients together until combined. This includes all purpose flour, cocoa powder, baking powder, baking soda, and salt.
STEP 3: In a large bowl, use a wire whisk to mix granulated sugar, light brown sugar, room temperature egg, vegetable oil, vanilla extract, and room temperature buttermilk together until smooth.


STEP 4: Pour the dry ingredients into the large bowl of mixed wet ingredients. Use a wire whisk to mix only until you see the dry ingredients disappear into the wet because overmixing will lead to dense cake cookies.


STEP 5: Whisk the hot water into the batter to smooth it out. Then, allow the batter to rest for 10 minutes, as this creates structure.
STEP 6: Divide the batter into tablespoon-sized dollops on your prepared pan.
STEP 7: Bake the chocolate cake cookies for 8-11 minutes until the tops are domed, slightly soft in the center, shiny on top, and a toothpick inserted into the center comes out with a few moist crumbs. Allow the cake disks to cool while preparing the filling.
Peanut Butter Filling


STEP 1: In a large bowl with a hand mixer or in the bowl of a stand mixer fitted with a paddle attachment, beat butter and powdered sugar together until smooth.
STEP 2: Add marshmallow fluff into the mixed butter and powdered sugar. Beat on medium speed until the ingredients combine.


STEP 3: Add peanut butter to the marshmallow fluff frosting. Then, beat on high speed until the peanut butter is dispersed evenly throughout. Use a rubber spatula to scrape down the sides and the bottom of the bowl while mixing.
STEP 4: Pour heavy whipping cream into the peanut butter icing. Finally, beat on high speed for about 3 minutes, as this creates a light and velvety frosting. If desired, transfer the frosting to a piping bag or zippable plastic bag with the corner snipped off.


STEP 5: Top half of the cooled cake disks with the whoopie pie filling. Place an unfrosted cake piece on top of the frosted disk to create a peanut butter chocolate sandwich.

Frequently Asked Questions
Whoopie pie filling is smooth, creamy, and velvety. This peanut butter whoopie pie filling is made with butter, powdered sugar, creamy peanut butter, marshmallow fluff, and heavy cream.
Store whoopie pies in a single layer (not stacked) on top of parchment paper at room temperature for up to 3 days, in the fridge for up to 5 days, or in the freezer for up to 4 months. Individually wrap them in cling wrap for cleanest serving and storing.

Expert Tips
- Measuring Flour: Use a kitchen scale to measure 327g exactly, or use a spoon to transfer flour from your container to your measuring cups. Then, use a knife to sweep across the measuring cups to level the flour.
- Room Temperature Ingredients: Make sure to use both a room temperature egg and room temperature buttermilk in the cake to create the lightest, most tender chocolate cake.
- Mixing: Mix the ingredients together only until you see the dry ingredients disappear to avoid dense cake.
- Individually Wrapping: To preserve these whoopie pies, individually wrap them in cling wrap because doing so will avoid the whoopie pies from sticking to each other.
- Avoid Heat: These whoopie pies are fragile and sticky. Keep them out of heat to prevent the filling from melting!
Related Recipes
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Chocolate Peanut Butter Whoopie Pies
- Prep Time: 20 minutes
- Cook Time: 10 minutes
- Total Time: 30 minutes
- Yield: 22 whoopie pies 1x
- Category: Chocolate, Chocolate Cake, Whoopie Pie, Peanut Butter
- Method: Bake
- Cuisine: American
Description
These Chocolate Peanut Butter Whoopie Pies are two moist chocolate cake cookies stuffed with peanut butter marshmallow filling. They are easy and made in one bowl with a whisk in 30 minutes.
Ingredients
For the Chocolate Whoopie Pies
- 2 ⅓ cups (327g) all purpose flour, properly measured
- ½ cup (41g) unsweetened cocoa powder
- 1 teaspoon baking soda
- ½ teaspoon baking powder
- ½ teaspoon salt
- ¾ cup (158g) granulated sugar
- ½ cup (120g) light brown sugar
- 1 large egg (50g), room temperature
- ½ cup (100g) vegetable oil
- 2 teaspoons vanilla extract
- 1 cup (240g) buttermilk, room temperature
- 2 tablespoons (30g) hot water
For the Peanut Butter Marshmallow Filling
- ⅔ cup (147g) unsalted butter, room temperature
- 1 ⅓ cup (160g) powdered sugar
- 1 cup (130g) marshmallow fluff
- ⅔ cup (190g) creamy peanut butter
- 1 ½ tablespoons (22g) heavy whipping cream
Instructions
For the Chocolate Whoopie Pies
- Preheat your oven to 350 degrees Fahrenheit and line baking sheets with parchment paper. This ensures that the sticky and moist whoopie pies do not stick to your pan after baking.
- In a medium bowl, whisk all purpose flour, cocoa powder, baking soda, baking powder, and salt until combined.
- In a large bowl, whisk granulated sugar, light brown sugar, room temperature egg, vegetable oil, vanilla extract, and room temperature buttermilk. Mix until smooth.
- Carefully, pour the dry ingredients into the wet ingredients before mixing with a wire whisk until smooth. The batter should be thick. Do not overmix, as mixing past when you see the dry ingredients disappear into the batter will create dense cake pieces. Pour 2 tablespoons of hot water into the batter and mix until smooth.
- Let the batter sit for 10 minutes at room temperature to allow the batter to gain structure and firm up.
- Divide the batter into 1-tablespoon-sized dollops on your prepared baking sheet. The dollops should be at least 2 inches apart because they will rise and spread as they bake.
- Bake the whoopie pies for 8-11 minutes until the tops are set and shiny. The centers should spring back when quickly poked with your pointer finger.
- Allow the whoopie pies to cool on your baking sheet for at least 15 minutes before filling.
For the Peanut Butter Filling
- In a large bowl with a hand mixer or in the bowl of your stand mixer fitted with a paddle attachment, beat room temperature butter until smooth.
- Slowly add powdered sugar to the bowl and beat on medium speed until the frosting is smooth.
- Add marshmallow fluff to the frosting and beat on high speed until incorporated. Use a rubber spatula to scrape down the sides and the bottom of the bowl before mixing again to ensure the frosting is combined.
- Add creamy peanut butter to your bowl. Beat on high speed until combined. Scrape down the sides and the bottom of the bowl again to properly spread the peanut butter throughout the filling.
- Pour heavy whipping cream into your frosting and beat on high speed for at least 3 minutes. This creates a light, smooth, and velvety filling.
- If desired, transfer the peanut butter filling to a piping bag or zippable plastic bag with the corner snipped off of it to create a makeshift piping bag.
For Assembly
- Top half of the cooled cake disks with peanut butter filling. If possible, leave a small rim around the outside to prevent the frosting from spilling out.
- Top the frosted cake pieces with an unfrosted cake piece to create a cake sandwich.
- Store the whoopie pies in single layers or individually wrapped in cling wrap to prevent the whoopie pies from sticking to one another.
Notes
Measuring: Measure your ingredients by using a kitchen scale to measure out the exact gram measurements. When measuring flour, specifically, do not pack flour into your measuring cups to avoid dense and dry cake pieces.
Bake Time: Only bake the cake disks until the tops are domed, shiny, and spring back in the center when poked quickly with your pointer finger. The cake pieces will continue to bake and firm up as they cool.
Individually Wrapping: For easiest and cleanest storing and serving, wrap each whoopie pie in cling wrap to avoid them from sticking to one another.
Keywords: Peanut Butter Whoopie Pies, Chocolate Whoopie Pies, Peanut Butter Cup Whoopie Pies, Marshmallow Filling
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