Chocolate Rum Cupcakes

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I think today is National Chocolate Cake day or something like that.  But who needs a holiday for chocolate or cake?  Cupcake Project combined a deep, dark chocolate cake with some rum and chocolate mousse frosting.  No holiday required for these delicious mini gems!

Chocolate Rum Cupcakes


  • 1/2 cup unsalted butter, room temperature
  • 1/4 cup blackstrap molasses
  • 1/4 cup + 2 tablespoons sugar
  • 1 ounce dark chocolate
  • 1 large egg
  • 1 large egg yolk
  • 1/2 teaspoon vanilla extract
  • 3 tablespoons sour cream
  • 1/2 cup all-purpose flour
  • 1/4 teaspoon salt
  • 1/4 teaspoon baking soda
  • 1/4 cup cocoa powder
  • 1/4 cup spiced rum

chocolate mousse frosting (see recipe below)

gold nonpareils, optional


  1. Preheat oven to 350 F.
  2. In a medium-sized mixing bowl or the bowl of a stand mixer, mix butter, molasses, and sugar until fully combined.
  3. Melt the chocolate in the microwave or in a double boiler.
  4. Once the melted chocolate is cool enough to touch, add it to the butter mixture and mix until just combined.
  5. Mix in egg and egg yolk until just combined.
  6. Mix in vanilla and sour cream until just combined.
  7. Sift together flour, salt, baking soda, and cocoa powder into a separate medium-sized bowl. Use a fork or a whisk to ensure that the ingredients are mixed well after sifting.
  8. Add dry ingredients to wet ingredients in three additions, mixing until just combined after each addition.
  9. Mix in rum until just combined.
  10. Fill mini cupcake liners 2/3 full and put in the oven.
  11. Check for doneness at 12 minutes – a toothpick inserted into the center of a cupcake should come out clean. If they are not done, check again every three minutes until they are done.
  12. Immediately remove cupcakes from the cupcake tin and place on a cooling rack or on the counter to cool to room temperature.
  13. Pipe with chocolate mousse frosting.
  14. Optionally, roll the bottom edge of the frosting in gold nonpareils.

Chocolate Mousse Frosting


  • 1 1/2 cups heavy whipping cream
  • 4 large eggs, room temperature
  • 2 tablespoons superfine sugar
  • 12 ounces dark chocolate (use the best chocolate you can find)
  • 1/4 cup unsalted butter, chopped into small pieces


  1. Whip the heavy whipping cream until it firmly holds peaks. Set aside in the refrigerator.
  2. Whip the eggs and sugar until very fluffy and thick – this takes about 10 minutes on high speed in a stand mixer.
  3. Melt the chocolate in a double boiler or in the microwave.
  4. Mix the butter into the melted chocolate until it is all melted.
  5. Add the chocolate/butter mixture a little bit at a time into the egg/sugar mixture, stirring well to fully incorporate the chocolate I do not suggest using an electric mixer for this as it is very easy to overmix using that method.
  6. Fold in the whipped cream.
  7. If you are serving right away, pipe onto cooled cupcakes and enjoy. Otherwise, cover and refrigerate the frosting. When ready to serve, whip the frosting for around 45 seconds at high speed to incorporate some air back into it. Then, pipe and serve. Alternatively, you could pipe onto cupcakes as soon as the frosting is done, refrigerate the frosted cupcakes, and bring the cupcakes back to room temperature before serving. I prefer to avoid refrigerating cupcakes when possible as I find that refrigeration changes their texture.

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