Preheat oven to 350F (175C). Line 36 mini muffin cups with paper or foil liners.

In a small bowl, whisk together flour, baking powder, and salt.

In a large bowl, beat butter until smooth and creamy.

Gradually beat in sugar until the mixture is light and fluffy.

Beat in eggs, one at a time, ensuring each is fully incorporated.

On low speed, alternately beat in the flour mixture and sour cream, beginning and ending with the flour mixture.

Add milk and vanilla extract; gently fold in the crushed cookie pieces.

Divide batter evenly among the prepared muffin cups. A piping bag can be used for cleaner distribution.

Bake for 15 minutes, or until a toothpick inserted into the center comes out clean.

Remove cupcakes from the oven and let cool completely on a wire rack.

For the frosting, in a clean bowl, beat confectioners' sugar, butter, sour cream, and vanilla extract until smooth and creamy.

Once the cupcakes are completely cooled, frost each with about 2 teaspoons of frosting.

Garnish with additional cookie crumbs, if desired.