These oatmeal sandwich cookies are a very nostalgic food for me.
My Grandma Thelma used to buy crunchy oatmeal cookies coated with icing.
Remember those? I loved those things! She used to slip them into my lunch bag and they were such a treat when I discovered them.
Now Granny, my mom’s mom, used to make soft oatmeal raisin cookies that folks just couldn’t get enough of.
Instead of messing with memories that hold such a soft spot in my heart, I created my own take on those traditional, soft oatmeal cookies, sandwiching a fluffy vanilla buttercream frosting between soft and chewy oatmeal cookies, sprinkled with raisins.
One great thing about these soft cookies is that they’re just as good on their own as they are with the sandwich filling layered between them.
Raisins or no raisins?
Personally, I am pro-raisin. I love the flavor burst they add to the cookie dough. And, everyone knows oatmeal and raisins were made to go together!
If you’re entirely against raisins in your oatmeal cookies you can omit them, but I do not recommend!
The raisins are one thing that elevates these oatmeal cream pies past the store-bought oatmeal cream pie we all grew up with.
Who’s ready to make the best oatmeal sandwich cookies you’ll ever have?
Oatmeal Cookie Sandwiches with Buttercream Filling
For Oatmeal Raisin Cookies
3/4 cup all-purpose flour
1/2 teaspoon ground cinnamon
3/4 teaspoon salt
1/4 teaspoon baking soda
8 tablespoons (4 ounces)
unsalted butter, softened, butter wrapper reserved
1 cup packed light brown sugar
1 large egg, beaten
1 teaspoon pure vanilla extract
11/2 cups old-fashioned oats
1/2 cup raisins, chopped if large
For Buttercream Filling
1/4 cup plus 2 teaspoons granulated sugar
2 large egg whites
1 cup (8 ounces) unsalted butter, cut into tablespoons and softened
1/4 teaspoon pure vanilla extract
For the cookies:
Preheat the oven to 325°F. Line 2 large prepared cookie sheets with parchment paper.
Whisk the flour, cinnamon, salt, and baking soda in a small bowl. Beat the butter and brown sugar in a large separate bowl until creamed together. Add the egg and vanilla and beat until well mixed. The mixture may look broken.
Add the flour mixture and fold until evenly moistened, then add the oats and raisins. Fold until evenly distributed.
Drop heaping tablespoons of dough onto the prepared baking sheets, spacing the rounds 2 inches apart. Use the reserved butter wrapper to push the rounds flat to a ½-inch thickness.
Bake one sheet at a time until the cookies are golden brown, 10 to 12 minutes. Place the sheets on wire racks and let cool completely.
For the filling:
Put the granulated sugar and egg whites in a heatproof bowl and set over a saucepan of simmering water. Whisk until the sugar is dissolved and the mixture is warm to the touch.
Remove from the heat and immediately whisk with an electric mixer until stiff peaks form. While whisking, add the butter 1 tablespoon at a time and beat until incorporated. Whisk in the vanilla. If the mixture looks broken, whisk in 1 tablespoon warm water. Beat until creamy, adding another tablespoon warm water if needed for the frosting to come together.
Divide the buttercream and use on the flat side of half the cookies and sandwich with the remaining cookies. Refrigerate until the filling is set.
Make ahead: The unfilled cookies keep at room temperature in an airtight container for up to 1 week. The filled cookies can be refrigerated for up to 3 days. These oatmeal sandwich cookies are a very nostalgic food for me.