Ingredients:
- 125g All-purpose flour
- 150g Granulated sugar
- 45g Dutch-process cocoa powder
- 0.75 tsp Baking soda
- 0.5 tsp Sea salt
- 1 Large egg, room temperature
- 120ml Full-fat sour cream
- 60ml Neutral oil (Grapeseed or Vegetable)
- 1 tsp Pure vanilla bean paste
- 120ml Hot brewed espresso
- 240ml Brut Champagne or Prosecco
- 225g Unsalted European-style butter, softened
- 350g Sifted confectioners' sugar
- 0.125 tsp Fine salt
Instructions:
- Reduce the champagne: Pour 240ml champagne into a small saucepan over medium-low heat. Simmer until reduced to exactly 60ml. Set aside to cool completely.
- Bloom the cocoa: Whisk the Dutch-process cocoa powder into the hot espresso until smooth to release deep flavor compounds.
- Prepare the batter: Preheat oven to 350°F (175°C) and line a muffin tin. In a stand mixer, combine flour, sugar, baking soda, and salt.
- Add sour cream, egg, oil, and vanilla. Mix on low until combined.
- Incorporate liquids: Slowly stream the warm cocoa-espresso mixture into the batter. The batter will be thin. Fill cupcake liners 2/3 full.
- Bake: Bake for 20 minutes or until the tops spring back when lightly touched. Cool completely on a wire rack.
- Make the frosting: Beat the softened European-style butter until pale and fluffy. Gradually add confectioners' sugar and fine salt. Slowly whip in the cooled champagne reduction and optional pink food gel until silken and aerated.
- Decorate: Pipe the frosting onto cooled cupcakes using a large open-star tip.