Makes 24 cupcakes
1 cup chardonnay
3/4 cup whole milk, room temperature
5 egg whites, room temperature
1 whole egg, room temperature
3 cups (345 g) cake flour
2 cups (400 g) sugar
4 teaspoons baking powder
3/4 tsp salt
12 tablespoons unsalted butter, cut into 12 pieces and softened slightly
Place chardonnay in a small saucepan over medium high heat. Bring to a rapid simmer. Simmer uncovered until reduced to 1/4 cup. Pour into a glass liquid measuring cup and let cool to room temperature. Add milk, egg whites and whole egg, set aside.
Heat oven to 350. Line two standard 12-cup muffin tins with paper liners.
Combine cake flour, sugar, baking powder, and salt in the bowl of your stand mixer with the paddle attachment. Beat on low to combine, about 10 seconds. Scatter the butter pieces over the dry ingredients and beat on medium speed until butter pieces are no larger than peas. Whisk the liquid ingredients briefly with a fork to combine. Add all but 1/2 cup of the liquid ingredients to the mixer and beat on medium high just until it becomes smooth, 30-60 seconds. Reduce speed to low and add the remaining liquid. Increase speed to medium high and beat just until incorporated.
Divide batter among muffin cups, filling them 2/3 full. If you bake them right away, they will have flat tops. If you want them to be domed, let the batter sit in the cups on the counter 20 minutes before baking. Bake 15-20 minutes until cupcakes will spring back and a toothpick inserted into the center comes out clean. Remove cupcakes to a wire rack and cool completely before frosting.