Preheat oven to 350 degrees Fahrenheit. Line a muffin pan with cupcake liners.

In a large bowl, combine all dry ingredients. Add wet ingredients and mix to combine.

Add batter to prepared pan. Bake 12 minutes for mini cupcakes; or 15–17 minutes for regular cupcakes, until tops are firm.

In the bowl of an electric mixer, beat margarine and shortening until smooth and fluffy.

Slowly add in sifted confectioners’ sugar and cocoa. Add vanilla, melted chocolate, and slowly add in milk, one tablespoon at a time, until frosting is desired consistency. You can add additional confectioners’ sugar or milk to thicken or thin the frosting as needed (thicker for piping, thinner for spreading).

Pipe onto cooled cupcakes.