Delicious oatmeal cookie whoopie pies filled with a creamy vanilla frosting. Soft, chewy oatmeal cookies sandwich a smooth, sweet filling for a perfect treat.
1 cup unsalted butter, softened
1 cup packed light brown sugar
1 large egg
1 teaspoon vanilla extract
1 1/2 cups all-purpose flour
1 teaspoon baking soda
1/2 teaspoon ground cinnamon
1/4 teaspoon salt
3 cups old-fashioned rolled oats
1/2 cup raisins
1/2 cup chopped walnuts
1/2 cup unsalted butter, softened (for filling)
1 1/2 cups powdered sugar
1 teaspoon vanilla extract (for filling)
2 tablespoons heavy cream
Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper.
In a large bowl, cream together 1 cup softened butter and brown sugar until light and fluffy, about 3 minutes.
Beat in the egg and 1 teaspoon vanilla extract until fully incorporated.
In a separate bowl, whisk together the flour, baking soda, cinnamon, and salt.
Gradually add the dry ingredients to the butter mixture, mixing until just combined.
Stir in the rolled oats, raisins, and chopped walnuts until evenly distributed.
Drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Bake for 10 to 12 minutes, or until the edges are golden and the centers are set.
Remove from the oven and allow cookies to cool on the baking sheets for 5 minutes, then transfer to wire racks to cool completely.
To make the filling, beat 1/2 cup softened butter until creamy.
Gradually add powdered sugar, beating until smooth.
Mix in 1 teaspoon vanilla extract and 2 tablespoons heavy cream until the frosting is light and fluffy.
Once cookies are completely cooled, spread or pipe a generous amount of filling onto the flat side of one cookie and sandwich with another cookie.
Repeat with remaining cookies to make 12 whoopie pies.
Serve immediately or store as directed.