Preheat oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a mixing bowl, whisk together flour, baking powder, baking soda, and salt.
In another bowl, beat butter and sugar until light and fluffy. Add eggs one at a time, beating well after each addition. Mix in vanilla extract.
Gradually add dry ingredients to the wet ingredients, alternating with buttermilk. Fold in crushed Oreo cookies.
Divide batter evenly among cupcake liners, filling each about ⅔ full. Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean. Let cool completely.
For the frosting, beat butter until creamy. Gradually add powdered sugar, beating until smooth. Mix in vanilla extract and milk until desired consistency is reached. Fold in crushed Oreo cookies.
Frost cooled cupcakes and enjoy!