Hello Friends! They’re finally here! Banana Oatmeal Sandwich Cookies – yum! You asked for the recipe on Instagram (if you’re not following along, why not?? Click that link & give your girl a follow!) and I’m here to please. These cookies are the perfect marriage of flavors and dare I say it, better than the OG oatmeal pie. You heard it here first folks.

Since these are basically an excuse to eat two cookies in one, you can fill them with whatever you like! I chose peanut butter filling, but chocolate, vanilla, fruit filling, marshmallow…you name it, you can fill these cookies with it.
Here’s what you’ll need to get started (for the cookies):
- Unsalted Butter
- Brown Sugar
- White Sugar
- Eggs
- Ripe Bananas
- Vanilla
- All Purpose Flour
- Cornstarch
- Salt
- Baking Soda
- Cinnamon
- Ginger
- Old-Fashioned Oats
What’s in an Oat?
This recipe calls for old-fashioned Oats – but what exactly does that mean? Below I explain all the differences between the many oats in your grocery store and why Old-Fashioned, or rolled oats are the perfect choice for these cookies. This info is curtesy of the great Quaker oats webpage.
Old Fashioned: Also called rolled oats, old fashioned oats are flat and flakey. They absorb more water and cook faster than steel-cut oats — usually in about 5 minutes — and are the oat of choice for granola bars, cookies, and muffins.
Steel Cut: These oats, which take about 20-30 minutes to prepare, are chopped into tiny pieces and have a tough texture before they are cooked. Also called Irish oatmeal, steel-cut oatmeal is chewier than rolled or instant.
Quick Cook: If you want stove-cooked oats but are in a hurry, these oats, which cook in one minute, are a great option. They can also be microwaved.
Instant Great for mornings when you need a quick bite, individually packed instant oats are a thinner, more finely chopped version of rolled oats. They microwave in minutes and have a soft texture.
It is probably pretty obvious after that run-down that old fashioned oats are the best choice for these banana-oatmeal sandwich cookies. They hold together and absorb the excess moisture that the bananas bring to the cookie batter so that they are not to wet or too dry. They also have a wonderful nutty-ness even without being toasted. I prefer to use bob’s red mills old fashioned rolled oats – like the ones pictured below – but you can use whatever brand you like if “old-fashioned” or “rolled oats” are in the title.
Let’s get stuffed.
So now let’s talk about the filling. No sandwich cookie is complete without a healthy dose of filling! I chose peanut butter here, and that’s what’s in the ingredient list, but feel free to fill them with whatever your favorite is! You really can’t go wrong.
Here’s what you need for the filling:
- Unsalted Butter
- Peanut butter
- Powdered Sugar
- Salt
- Milk
- Vanilla
This is a super simple peanut butter buttercream recipe that works for all sorts of baked goods – not just these cookies so make sure you save it for another baking project if you’re not using it here!
Cookies! Assemble!

There is just something so satisfying about putting these cookies together. Once the cookie are completely (and I mean completely) cooled, you can slather, pipe, swirl your filling in-between. I usually choose to pipe my filling but you can absolutely use the back of a spoon to achieve the same effect. I find piping gives me more control, but whatever you have available to you in your own kitchen.
So that’s it guys – I hope you love these cookies as much as we do! Leave me a comment down below and let me know what you think! Xo
Happy Baking!
Danielle
Looking for more cookies?? Click here!
Brown Butter Chocolate Chip Cookies

Banana Oatmeal Sandwich Cookies
Ingredients
- ½ Cup Unsalted Butter
- ¾ Cup Brown Sugar firmly packed
- 2/3 Cup White Sugar
- 1 Large Egg
- ¾ Cup Ripe Bananas about 2 large
- 1 tsp Vanilla
- 1 ¾ Cups All Purpose Flour
- 1 ½ tsp Cornstarch
- 1 ½ tsp Salt
- 1 tsp Baking Soda
- 1 tsp Cinnamon
- ½ tsp Ginger
- 2 ¾ Cups Old-Fashioned Oats
For the Frosting:
- ½ Cup Unsalted Butter
- ½ Cup Peanut butter
- 1 Lb Powdered Sugar
- ¼ tsp Salt
- 2 tbsp Milk
- 1 tsp Vanilla
Instructions
- Preheat the oven to 350 Deg F & line baking sheets with parchment paper
- In the bowl a stand mixer fitted with the paddle attachment, beat butter and sugars on medium speed until fluffy. About 2-3 minutes. Scrape down the bowl as necessary. Add the egg and mix until combined. Follow with banana and vanilla.
- In a medium bowl, whish flour, cornstarch, salt, baking soda, cinnamon, and ginger. Add flour mixture to butter all at once and mix on medium low until nearly combined.
- Add the oats and mix until combined.
- Using a cookie scoop (I used a number 24) scoop dough onto prepared pans. Bake until the edges are set and the centers still seem slightly under-done. About 8-10 minutes.
- Allow cookies to cool on the pan for 5 minutes before moving to a cooling rack to cool completely.
- For the frosting, in the bowl of a stand mixer fitted with a paddle attachment, mix butter and peanut butter together until combined.
- Slowly add the powdered sugar, adding milk as needed to thin the frosting. Add salt and vanilla
- Increase speed to medium high and whip until light and fluffy.
- Place frosting in a piping bag fitted with a star tip or into a zip-top bag. Pipe frosting on the flat side of a cookie and place another on top creating a sandwich.
- Serve immediately or store in an airtight container in the refrigerator for up to 3 days.
Recipe Notes
Recipe inspired by the BakeFeed Magazine
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