Preheat oven to 350 F. In a large bowl, whisk together flour, sugar, salt, and baking powder. Add in eggs, milk, vegetable oil, and vanilla extract, whisk until smooth. Fold in Oreo cookies.
Evenly divide cupcake batter between 12 lined cupcake tins. Bake for 15-18 minutes. Let cool completely. For the cookies and cream buttercream frosting, beat softened butter with powdered sugar, milk, vanill extract, and crushed oreos, until creamy.
Pipe or spread frosting onto cooled cupcakes.