Oatmeal Whoopie Pies
Soft oatmeal cookies hold a generous amount of marshmallow buttercream. These are sweet, nostaglic, and delicious.
Servings: 12 servings
Equipment
- Electric Mixer
- 4 Baking sheets
- Mixing Bowls (medium and large sizes)
- Measuring cups and spoons
- Rubber spatula
- Cookie scoop or large spoon
- cooling rack
Ingredients
Cookies
- 1 cup unsalted butter softened
- 1 cup brown sugar packed
- 1 cup granulated sugar
- 2 eggs
- 2 teaspoons vanilla extract
- 2 cups all-purpose flour
- 1½ teaspoons cinnamon
- 1 teaspoon baking soda
- 1 teaspoon baking powder
- 1 teaspoon salt
- ½ cup milk whole preferred, but 2% is okay
- 1½ quick oats not instant
- 1½ old-fashioned oats
Marshmallow Filling
- 12 tablespoons unsalted butter softened
- 1 cup powdered sugar
- 1 teaspoon vanilla
- ¼ teaspoon salt
- 2 cups marshmallow cream such as Marshmallow fluff brand
Instructions
Make the Cookies
- Prep. Preheat your oven to 350°F (175°C) with oven racks in upper-middle and lower-middle positions. Then, line four baking sheets with parchment paper.
- Combine the wet ingredients. Beat the softened butter, brown sugar, and granulated sugar at medium speed until light and fluffy for about 5 minutes. Then, add the eggs one at a time, followed by the vanilla extract. Continue beating until well combined, scraping down the sides of the bowl as needed.
- Combine the dry ingredients. Whisk together the flour, cinnamon, baking soda, baking powder, and salt in a separate large bowl.
- Combine both. With the mixer on low speed, add half of the dry ingredients to the butter mixture, then half of the milk. Repeat, ending with the dry ingredients, until all are incorporated. Mix just until combined. Add the quick and old-fashioned oats, stirring by hand or on the lowest mixer setting until evenly distributed.
- Shape. Scoop 3–4 tablespoons of dough per cookie onto the prepared baking sheets, spacing them about 2 inches apart. Each baking sheet should fit about six cookies; you’ll have 16–24 cookies.
- Bake. Bake the cookies at 350°F for 15–18 minutes, rotating the baking sheets between racks halfway through baking. The cookies should look set and slightly golden at the edges, and a toothpick should come out clean. Transfer to a cooling rack and allow them to cool completely.
Make the Filling
- Make the filling. In a clean mixing bowl, beat the softened butter and powdered sugar on medium speed until smooth and fluffy, about 3–4 minutes. Add the vanilla extract and salt, mixing until combined. Add the marshmallow cream and beat until the filling is smooth and fully combined. If the filling seems too soft, refrigerate for 10–15 minutes to firm up.
- Assemble the whoopie pies. Spread about ¼ cup of the marshmallow filling onto half the cookies’ flat side. Top with the remaining cookies, pressing gently to create a sandwich. Serve immediately, or refrigerate the whoopie pies for a firmer filling.
Notes
Make sure your butter, eggs, and milk are at room temperature before you start mixing. This helps them blend well and makes your cookies have a better texture.
Check your baking powder and baking soda to make sure they’re fresh. These ingredients lose power over time, so always look at the expiration dates. Fresh leavening agents will help your cookies be soft and light instead of flat or hard.
Using too many oats can make the cookies dry and heavy. Measure your oats carefully for the right amount and get that chewy texture.
Let the cookies cool completely before adding the filling. If they’re even a little warm, the marshmallow filling will melt and slide off, making a sticky mess.
If you like a lot of filling, think about making an extra half-batch to add more to each whoopie pie without running out.
After you put the whoopie pies together, chill them in the fridge for 15–20 minutes. This helps the filling set and makes them easier to handle, especially if you want to save some for later.
Try adding mini chocolate chips, shredded coconut, or raisins to the cookie dough for something different. Just don’t add too much so your cookies stay soft.