Brown the Butter: In a medium saucepan, melt the unsalted butter over medium-low heat with a split vanilla bean until golden brown, about 5-7 minutes.

Make the Frosting: Beat softened brown butter with cream cheese until smooth, then gradually add powdered sugar.

Prepare the Batter: Preheat oven to 350°F (175°C). Whisk cake flour, sugar, baking powder, and salt; add cooled brown butter.

Incorporate Wet Ingredients: Add eggs one at a time, then buttermilk and vanilla extract, mixing until smooth.

Bake and Cool: Fill cupcake liners and bake for 18-20 minutes. Cool on a wire rack.

Frost the Cupcakes: Apply frosting to cooled cupcakes using a knife or piping bag.

Serve and Enjoy: Serve at room temperature, optionally with berries or vanilla ice cream.