I love sandwiches. And I love cookies.
But would I prefer sandwiches inside my cookies or cookies inside my sandwiches? I’ll admit I’m more likely to say the latter—cookies tucked into a sandwich sounds irresistible.
Most of my go-to savory sandwiches involve crisp bacon, toasted bread, a smear of aioli and a soft-poached egg. That profile doesn’t exactly scream “cookie companion,” so I chose a sweeter route: buttercream. Not just any buttercream, though—the marshmallow buttercream.
Simple, but delightful: butter, marshmallow fluff (homemade or store-bought), powdered sugar and vanilla. It’s decadent without being complicated.
Believe it or not, it’s one week until Christmas and these were the first treats I baked. I usually have a long holiday baking list, and this year was no different—except these didn’t last long enough to worry about what came next.
I tend to procrastinate a bit; I promised myself I’d start earlier but ended up planning to bake late into the night with a holiday playlist that jumps from Mariah Carey to Barry Manilow, N*SYNC and a little modern pop. Holiday music gives me that festive push.
For the cookie base I adapted a tried-and-true chewy oatmeal chocolate chip recipe I’ve used for years. I ended up swapping baking powder for baking soda on purpose and the result was a slightly thinner cookie with an exceptional chew. The texture—crispy at the edges, soft and chewy in the middle—is exactly what I wanted for sandwiching.
The chewiness is almost unbearable in the best way. These cookies are thin and a bit crisp, but still tender and packed with oat texture. Paired with the fluffy marshmallow buttercream, they become a little sandwich of holiday joy.
I’ll confess I daydream about diving face-first into the center of a stack of these cookies and staying there for a while—figuratively, of course. I love everything about the season: the bustle, the lights, the excuse to sparkle and indulge. It’s a time to be festive, wear glitter if you want, and yes, enjoy cookies for breakfast before a brisk run.
Chewy Black + White Chip Oatmeal Sandwich Cookies with Marshmallow Buttercream Filling
Yield:
2 dozen cookies, 1 dozen sandwiches
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Ingredients
- 1/2 cup unsalted butter, at room temperature
- 1/2 cup granulated sugar
- 1/2 cup loosely packed brown sugar
- 1 large egg
- 2 teaspoons vanilla extract
- 1 1/4 cup all-purpose flour
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 3/4 cups rolled oats
- optional: 1–2 tablespoons milk, if dough is very crumbly
- 2/3 cup dark chocolate chips
- 2/3 cup white chocolate chips
Marshmallow Buttercream Filling
- 1/2 cup unsalted butter, softened
- 1 cup marshmallow cream, homemade or store-bought
- 1/2 cup powdered sugar
- 1 teaspoon vanilla extract
- 1 pinch salt
Instructions
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Preheat the oven to 375°F (190°C).
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Cream the butter in the bowl of an electric mixer until smooth. Add both sugars and beat on high until light and fluffy, about 2–3 minutes. Add the egg and vanilla and mix until combined.
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With the mixer on medium, stir in the flour, baking soda and salt. Mix in the oats just until combined. If the dough seems too crumbly, add 1–2 tablespoons milk. Fold in both kinds of chocolate chips. Refrigerate the dough for 30 minutes.
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Roll dough into even 1-inch balls and place them 2 inches apart on a nonstick baking sheet. Bake 9–11 minutes, until the edges are just golden. Let cookies cool completely before assembling with the buttercream.
Marshmallow Buttercream Filling
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Beat the softened butter until creamy. Add the marshmallow cream and beat on medium until combined, about 2 minutes. Add powdered sugar, vanilla and a pinch of salt, mixing on medium for another minute. Scrape the bowl and beat on high for 2–3 minutes until light and fluffy.
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Pipe or spoon a generous dollop of buttercream onto the flat side of one cookie and sandwich with a second cookie. Repeat until all cookies are assembled. Store in an airtight container.
Notes
Did you make this recipe?
I appreciate you so much!
A cookie cannonball into the center of a gooey sandwich is exactly the kind of indulgence I welcome this season.