Step 1: Prepare the Cupcake Batter
Preheat oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a medium bowl, whisk together flour, cocoa powder, baking soda, baking powder, and salt.
In a large bowl, combine sugar, brown sugar, oil, eggs, buttermilk, and vanilla extract. Mix until smooth.
Add dry ingredients to the wet mixture and stir until just combined. Fold in the crushed cookies.

Step 2: Bake the Cupcakes
Divide the batter evenly among the liners, filling each about ⅔ full.
Bake for 16–18 minutes, or until a toothpick inserted in the center comes out clean.
Let cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Step 3: Make the Buttercream Frosting
In a large bowl, beat the softened butter until fluffy (about 2–3 minutes).
Gradually add powdered sugar, beating between each addition.
Add vanilla and cream or milk, and beat until light and creamy.
Stir in the finely crushed cookies.
Divide the frosting into three bowls. Tint one red, one blue, and leave one white.

Step 4: Pipe the Patriotic Swirl
Spoon each color of frosting into separate sections of a piping bag fitted with a large star tip.
Alternatively, use three small piping bags placed into one larger bag to create a swirl.
Pipe onto cooled cupcakes in a tall, elegant swirl.
Top with patriotic sprinkles if desired.