In a large mixing bowl combine all the cake ingredients except the oreos. Combine and mix well. Stir in the crushed oreos and mix.
Prepare the cupcake liners by filling them about 2/3 cups full. Bake for about 20 minutes or until the toothpick comes out clean. Allow the cupcakes to cool completely before frosting them.
To prepare the frosting, in a mixing bowl beat the butter, cream cheese, vanilla, and salt and mix until creamy and smooth.
Add in the powdered sugar 4 tbsp of milk. Beat well and if they mixture is too thick, add in another tablespoon of milk. Stir in the oreos and pipe onto the cooled cupcakes.
Store the cupcakes in the refrigerator for up to 5 days.