To make the cupcakes:

1. Preheat the oven to 175°C (347°F) and line a cupcake pan with cupcake liners.

2. In a large bowl, whisk together the wet ingredients: eggs, milk, coffee, oil, and vanilla extract. Add the granulated and brown sugars, mixing until smooth.

3. Sift together the dry ingredients: flour, cocoa powder, baking powder, baking soda, and salt.

4. Gradually add the dry ingredients to the wet ingredients, folding until just combined. Gently fold in the crushed Oreos.

5. Spoon the batter into the cupcake liners, filling each about ¾ full. Bake for 20-22 minutes, or until a toothpick inserted comes out clean.

6. Allow the cupcakes to cool completely on a wire rack.

To make the frosting:

1. Crush the Oreos into fine crumbs using a food processor or ziplock bag.

2. Cream the butter in a stand mixer or with a hand mixer until light and fluffy.

3. Gradually add powdered sugar, continuing to whip until smooth and fluffy.

4. Add the crushed Oreos, vanilla extract, salt, and heavy cream. Whip until smooth and creamy.

5. Pipe or spread the Oreo frosting onto the cooled cupcakes, and garnish with extra crushed Oreos if desired.