Oatmeal Whoopie Pies

If you love oatmeal cookies, you’ll really love this whoopie pie version. They are giant soft cake-like cookies filled with the most amazing marshmallow filling. There’s something about adding filling to a cookie that just makes it better.

These are quite easy to make. You’re just making cookies and icing really, then putting them together.

Ingredients and Tools You’ll Need

Personally, I like the blend of two types of oats. But if you only have one kind you can use that, though the texture will be different. If you do use the quick oats, make sure it’s not the instant oats. If you don’t want to use marshmallow cream, you can just use your favorite buttercream recipe.

Use a medium cookie scoop (or about a 1/4 cup) for perfectly even cookie cakes.

This will make about 12 whoopie pies. If you’d like to double or triple this recipe, you can make adjustments in the recipe card at the bottom of this post.

Equipment

• Parchment paper
• Electric Mixer
• 4 Baking sheets
• Mixing Bowls (medium and large sizes)
• Rubber spatula
• Medium cookie scoop (¼ cup 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 cups quick oats not instant
• 1½ cups 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

How to Make Oatmeal Whoopie Pies

Step One: Get Ready

Heat your oven to 350°F. Then, line four baking sheets with parchment.

Step Two: Make the Cookie Dough

Beat the butter and both sugars for 5 minutes until fluffy. Add the eggs one at a time, then the vanilla, mixing after each. Scrape the bowl.

In another bowl, whisk the flour, cinnamon, baking soda, baking powder, and salt.

Add half the flour mixture to the butter mixture, then half the milk. Repeat, keeping the mixer on low. Stir in both the oats.

Step Three: Shape and Bake

Scoop 3-4 tablespoons of dough per cookie onto a parchment lined baking sheet. Space them 2 inches apart. You’ll get about 6 per sheet.

Bake for 15-18 minutes. Switch the pan positions halfway through. They are done when the edges are set and lightly golden. Let them cool completely.

Step Four: Make the Filling

Beat the butter and powdered sugar until smooth, about 3-4 minutes. Add the vanilla, salt, and marshmallow fluff. Beat until combined. If it’s too soft, pop it in the fridge for 10-15 minutes.

Step Five: Put Them Together

Put ¼ cup filling on the flat side of half the cookies. Top with remaining cookies. Press gently.

Eat right away or refrigerate for firmer filling.

Storage Instructions

These will keep just fine at room temperature for a day or two as long as your kitchen is cool. In a warm kitchen, the filling might get too soft. In that case, just pop them in the fridge.

You can freeze leftovers, but layer them in between layers of wax paper so they don’t stick together in the freezer. I usually just let them defrost on the counter for 20 minutes and eat them partially frozen.

What to Serve

These are perfect when you need something that kids and adults will both love. Serve these outside with these classic foods.

• Nearly everyone loves hot dogs and hamburgers.
• Classic blackberry lemonade is sweet and tart. Plus it’s super pretty to serve.
• Cucumber and onion salad is what you remember your mom bringing in a big container to any summer meal.
• Old-fashioned macaroni salad has just the right balance of creamy and crunchy.

Questions and Troubleshooting

More Whoopie Pie Recipes

I turn nearly any cookie into a whoopie pie. I may have a problem.

• Vanilla whoopie pies use vanilla bean paste in the filling to give it that lovely vanilla flavor.
• Chocolate chip whoopie pies take a chocolate chip cookie and makes it even better.
• Strawberry whoopie pies are a pretty pink color that is perfect for a party.

Printable Recipe