Preheat oven to 350 degrees F. In a large mixing bowl mix cocoa powder and baking soda. Pour boiling water over the mixture and stir until combined.
In a separate large mixing bowl mix melted butter, oil, sugar, vanilla, salt, and eggs until combined. Blend in cocoa mixture and heavy cream.
Gradually stir in flour a little at a time and stir until just combined.
Divide batter evenly between lined cupcake bakers. Bake for 20-22 minutes or until a tooth pick inserted in the center comes out clean. Cool completely.
<b>For the Mint Chocolate Chip Buttercream:</b>
Stir butter until light and fluffy. Stir in mint and vanilla extracts.
Gradually stir in powdered sugar a little at time, adding milk as needed.
Stir in food coloring if desired. Fold in mini chocolate chips.
Scoop a generous amount of frosting onto the cupcakes with an ice cream scoop.