Ingredients
1 2/3 cup all-purpose flour (213g)
1 cup granulated sugar (200g)
1/4 tsp baking soda
1 1/2 tsp baking powder
1/4 tsp kosher salt
3/4 cup unsalted butter (170g, melted)
3 egg whites (room temperature)
1 tbsp vanilla extract (15mL)
1/2 cup sour cream (120mL, room temperature)
1/2 cup whole milk (120mL, warm)
2 lb confectioners sugar (900g, sifted)
1 lb unsalted butter (450g, room temperature)
1 tsp vanilla extract
1 tbsp heavy cream
1 pinch kosher salt
1 tsp whole milk
Instructions
For the Cupcakes:
Preheat oven to 350 degrees F. Place cupcake papers in a cupcake pan.
Sift the flour, sugar salt, baking soda and powder into a large bowl, and whisk together.
Separate the eggs. You can use the yolks for a custard or a batch French buttercream.
In another bowl, whisk together the wet ingredients until combined. (The batter may be clumpy, do not worry!)
Add the wet ingredients to the dry ingredients. Mix until combined.
Distribute the batter evenly into cupcake papers, filling each paper with about 2/3 the way up.
Bake for about 18 minutes or until centers are springy to the touch.
For the Buttercream:
In a stand mixer fitted with a paddle attachment, cream the room temperature butter. Add in the confectioners sugar in two batches. Add salt, milk, cream and vanilla. Mix until fluffy.
Transfer to a piping bag.
Pipe a large dollop of buttercream on each cupcake.