Dark Chocolate Cassis Cupcakes
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Makes 6 cupcakes, but you will probably have some leftover buttercream. The buttercream recipe makes enough to generously frost about 8 cupcakes.
Ingredients
For the chocolate cupcakes:
  • 70g (or ⅓ cup + 1 teaspoon) granulated sugar
  • 70g (¼ cup + 1 tablespoon, packed) light brown sugar
  • 30ml (or 2 tablespoons) sunflower oil
  • ½ large egg*
  • 60ml (or ¼ cup) hot water**
  • ¼ teaspoon instant coffee powder
  • 65ml (or ¼ cup + 1 teaspoon) buttermilk***
  • ⅛ teaspoon vanilla extract
  • 50g (or ⅓ cup + 1 tablespoon) all-purpose flour
  • 40g (or ⅓ cup + ½ teaspoon) Dutch-processed cocoa powder
  • ⅜ teaspoon baking soda
  • ⅛ teaspoon baking powder
  • big pinch of salt
For the buttercream:
  • 2 large egg whites (about 65g or ¼ cup)
  • 125g (or ½ cup + 2 tablespoons) granulated sugar
  • 113g (or ½ cup) unsalted butter, cubed and softened at room temperature
  • 100g (or ⅓ cup – 1¾ teaspoons) strained blackcurrant or cassis jam, I used Bonne Maman
To fill and decorate the cupcakes:
  • 6-8 teaspoons of blackcurrant or cassis jam, I used Bonne Maman
  • 30g (or 1 ounce) dark chocolate
Instructions
First make the chocolate cupcakes:
  1. Preheat oven to 175°C/350°F (standard oven setting) and line a 6-cup muffin pan with cupcake liners.
  2. In a medium-sized bowl, whisk together sugars, oil and the egg (so ½ large egg).
  3. In a glass, combine hot water and coffee powder and stir until the coffee has dissolved. Add the buttermilk and the vanilla extract and stir until combined. Add this buttermilk mixture to the sugar mixture. Whisk until combined.
  4. Add the flour, cocoa powder, baking soda, baking powder and salt and whisk until the batter comes together.
  5. Divide the batter evenly over the 6 muffin cups (filling them three quarters full). Gently rap the pan on the counter once to remove any air bubbles, then bake in the middle of the oven for 18-20 minutes, or until a tester inserted into one of the cupcakes comes out clean.
  6. Remove from the oven and allow the cupcakes to cool to room temperature. Once cool, the cupcakes can be frosted.
While the cupcakes are in the oven, make the Swiss cassis buttercream:
  1. Combine egg whites and sugar in a medium-sized heatproof bowl (or the bowl of a double boiler) and whisk until incorporated. Set the bowl over a pan of simmering water, making sure the water doesn’t touch the bottom of the bowl, and gently heat the egg mixture, whisking continuously, until the sugar has dissolved. You can check whether the sugar has dissolved by rubbing a bit of the mixture between your fingers; you should no longer feel any sugar crystals. At this point, you can either pasteurize the mixture, or use the unpasteurized egg whites.
  2. If you want to pasteurize the egg whites, continue to heat the mixture, whisking continuously, until the mixture reaches a temperature of 71°C/160°F. You will need a sugar or candy thermometer, or a multimeter to properly register the temperature. If you decide not to pasteurize the egg whites, proceed with the next step.
  3. Remove the egg white mixture from the heat and, using an electric whisk fitted with the whisk attachment, beat the mixture until the resulting meringue holds stiff peaks and has cooled to room temperature. The bottom of the bowl should also have cooled to room temperature.
  4. Add the cubed, softened butter one cube at a time, mixing well after each addition. If the mixture looks like it it’s separating after you’ve added all the butter, don’t panic. Just keep beating the mixture and the buttercream will magically come together again. If the buttercream is too soft to pipe, the butter was too hot when you added it. In that case, place the bowl with the soft buttercream in the fridge for about 20 minutes, then mix again. The buttercream should firm up.
  5. When the buttercream looks smooth and creamy, beat in the strained cassis or blackcurrant jam and mix until well combined. Use the buttercream immediately (or within a few hours) or store in an airtight container in the fridge for up to 2 weeks. Allow buttercream that has been refrigerated to come to room temperature, then beat with the mixer until smooth and spreadable again before using it.
To assemble the cupcakes:
  1. Using a serrated knife, make a hollow in the center of each cooled cupcake. Fill with a teaspoon of blackcurrant or cassis jam. Transfer the cassis buttercream to a piping bag fitted with a large star tip and frost the cupcakes with a swirl of buttercream. Melt the chocolate in the bowl of a double boiler, then use a teaspoon to drizzle the melted chocolate over the top of the cupcakes.
  2. Frosted cupcakes can be stored in an airtight container in the fridge for up to 3 days.
Tip:
  1. Use the leftover buttercream and melted chocolate to make cassis creams!
Notes
* crack one large egg in a small bowl. Using a fork, whisk the egg until the white and yolk are well mixed, then only use half of for this recipe (28g or 1½ tablespoons).
** instead of using hot water and instant coffee powder, you can use 60ml (¼ cup) of coffee.
*** instead of buttermilk, you can use regular milk or make your own buttermilk by combining 60ml (¼ cup) milk with 1 teaspoon of lemon juice or white vinegar
Recipe by The Tough Cookie at https://thetoughcookie.com/2016/02/22/dark-chocolate-cassis-cupcakes/