Ingredients
Method
- Preheat the oven to 350°F (175°C). Line a 12-cup muffin pan with cupcake liners.
- Whisk together cake flour, baking powder, baking soda, and salt in a medium bowl.
- Beat butter and sugar on high speed for 2–3 minutes until pale and fluffy.
- Add egg whites and vanilla. Beat until smooth and glossy.
- Alternate adding dry ingredients and buttermilk, mixing gently until just combined.
- Divide batter evenly into liners, filling each ⅔–¾ full. Bake 16–18 minutes, until a toothpick comes out clean. Cool completely.
- Melt white chocolate, butter, and cream over a double boiler until smooth. Cool, then whip until light and fluffy.
- Beat butter and salt for the buttercream on high speed until very pale. Mix in melted white chocolate, then powdered sugar. Whip until fluffy.
- Core cooled cupcakes, fill with white chocolate ganache, and pipe buttercream on top. Decorate as desired.
Notes
Use high-quality white chocolate for the smoothest texture. Ensure all ingredients are at room temperature before starting. Cupcakes can be baked a day ahead and assembled before serving. Chill ganache briefly if too soft, and allow cupcakes to come to room temperature before serving.
