1. Preheat the oven to 350°F and line a 12 cup muffin pan with cupcake liners.

2. In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt.

3. In a large mixing bowl, beat the butter and sugar until light and fluffy.

4. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

5. In a small bowl, combine the buttermilk and green food coloring.

6. Add the dry ingredients to the butter mixture in batches, alternating with the buttermilk mixture, and mix just until combined.

7. Stir in the vinegar gently at the end.

8. Divide the batter evenly among the cupcake liners, filling each about two thirds full.

9. Bake for 18 to 22 minutes, or until a toothpick inserted into the center comes out clean.

10. Cool the cupcakes in the pan for 5 minutes, then transfer them to a wire rack to cool completely.

11. To make the frosting, beat the cream cheese and butter until smooth.

12. Add the powdered sugar and vanilla extract, then beat until creamy.

13. Add heavy cream or milk a little at a time until the frosting reaches a smooth piping consistency.

14. Frost the completely cooled cupcakes and serve.