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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.

Oatmeal Sandwich Cookies stacked on a white plate

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. 

Oatmeal Cookies Ready to Bake

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.

Oatmeal-Sandwich-Cookie-with-Vanilla-Buttercream-Frosting ready to top

This recipe makes about 25 little sandwich cookies. They make a great edible gift, party or holiday treat and they freeze well too!

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Oatmeal Sandwich Cookies with Vanilla Bean Buttercream

5 from 3 votes
Prep: 20 minutes
Cook: 10 minutes
Total: 30 minutes
Course: Dessert
Cuisine: American
Calories: 306
Servings: 25 sandwich cookies
If you don’t feel like making the buttercream, the oatmeal cookies are wonderful on their own. You could add chocolate chips or raisins too.


For the Cookies:

  • 2/3 cup unsalted butter at room temperature
  • 1/2 cup granulated sugar
  • 3/4 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:


Calories: 306kcal | Carbohydrates: 34g | Protein: 2g | Fat: 18g | Saturated Fat: 10g | Cholesterol: 48mg | Sodium: 175mg | Potassium: 81mg | Fiber: 1g | Sugar: 24g | Vitamin A: 500IU | Calcium: 33mg | Iron: 0.6mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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  1. Cheyanne @ No Spoon Necessary says:

    5 stars
    Thalia’s blog is absolutely BEAUTIFUL! Her photos are stunning and creations are just genius, right?! Love that she inspired these stellar sandos! I have a SERIOUS weakness for oatmeal sandwich cookies. Like, I can NOT be trusted around them, because I will eat them all. I’m not kidding! 😉 So you know I’m just dying over these, Marissa!!! They look fabulous and that vanilla buttercream looks dangerously delicious!! Gorgeous photos, my dear! I’m drooling! Pinned! Cheers! I hope you and your family have a beautiful Easter! <3

    1. Marissa says:

      Aww…thank you, Cheyanne!! Hope you have a beautiful Easter too! xo

  2. Colormelimitlessly by Kaisha says:

    This looks so good!

    1. Marissa says:

      Thanks, Kaisha!

  3. Jess @ says:

    These oatmeal sandwich cookies look amazing! Love that they’re filled with the amazing and very delectable vanilla buttercream! Yum- thanks for sharing your lovely recipe!

    1. Marissa says:

      What a sweet note, thank you!

  4. Kristi @ Inspiration Kitchen says:

    These look absolutely fabulous Marrisa (pinned)! I wanted to stop by today to wish you a Happy New Year! Here’s looking forward to wonderful things for you and your family in 2015!

    1. Marissa says:

      Happy New Year, Kristi! xo

  5. Sonali- The Foodie Physician says:

    These look so delicious and your photos are gorgeous! I just took my first look at Thalia’s blog and I totally see what you mean!

    1. Marissa says:

      Thank you, Sonali. She’s a talent, isn’t she!