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Oatmeal Sandwich Cookies with Fluffy Vanilla Buttercream Frosting will make you weak in the knees they're so good. I'm not kidding! They're also very rich. So make the cookies tiny - about a tablespoon of dough per cookie - and you'll end up with cookies that are two or three bites of heaven.
These oatmeal sandwich cookies have a satisfyingly complex flavor and texture, one that you'll want to savor. Made with whole grain flour, thick rolled oats, crunchy walnuts, and ample cinnamon. And for the sandwich filling, I went with fluffy vanilla buttercream frosting - my favorite.
When you make these, I recommend that you make them very small, just one or two bites. They are incredibly rich. I love this 1 tablespoon scoop, it's perfect for scooping cookie dough and frosting for the middle.
This recipe makes about 25 little sandwich cookies. They make a great edible gift, party or holiday treat and they freeze well too!
Oatmeal Sandwich Cookies with Vanilla Bean Buttercream
For the Cookies:
- ⅔ cup unsalted butter at room temperature
- ½ cup granulated sugar
- ¾ cup brown sugar packed
- 1 egg
- 1 tablespoon vanilla extract
- 1 tsp white vinegar
- ½ tsp salt
- 1 tsp baking powder
- ½ tsp baking soda
- 1 tbsp ground cinnamon
- 1 cup white whole wheat flour 120 g
- 2 ½ cups old-fashioned oats 240 g
- ½ cup chopped walnuts 75 g
- 1 recipe Fluffy Vanilla Buttercream Frosting
For the Oatmeal Cookies:
- Preheat oven to 350°F.
- Line a baking sheet with parchment paper.
- In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon and salt. Set aside.
- Add butter and sugars to the bowl of a stand mixer fitted with the paddle attachment. Beat at low speed until combined; increase speed and beat until fluffy, 2 to 3 minutes more. Add egg, vanilla and vinegar; beat well, scraping down sides of bowl as needed. Add flour mixture – cover mixer with a kitchen towel to protect your counters from a flour flurry. Start at low speed to stir, then increase to medium and mix until fully combined. Add rolled oats and walnuts; mix just until combined.
- Scoop dough into walnut sized balls (my favorite cookie scoop) and arrange about 2-inches apart on prepared baking sheet. Bake for 8 to 10 minutes, until golden brown on the edges and still soft in the middle. Let rest a few minutes on baking sheet before transferring to a cooling rack. Repeat process with remaining dough.
To Assemble Oatmeal Sandwich Cookies:
- Once the cookies have cooled, spread your desired amount of fluffy vanilla buttercream frosting on the bottom side of one cookie, and top with another.