For the cupcakes:
1 1/2 cups cake flour
1 1/2 tsp baking powder
1/4 tsp salt
1 vanilla bean, split lengthwise
8 tbsp. unsalted butter, at room temperature (1 stick)
3/4 cups sugar
2 large eggs, at room temperature
3/4 cup buttermilk, at room temperature
2 tsp vanilla extract
Preheat the oven to 350° F. Line a muffin pan with paper liners. Set aside.
In a medium mixing bowl, combine the cake flour, baking powder and salt. Whisk together and set aside. Add the butter to the bowl of an electric mixer fitted with the paddle attachment. Scrape the vanilla bean seeds into the bowl of the mixer with the butter and discard the pod (or reserve for another use.) Beat on medium-high speed for 3 minutes, until light and creamy in color. Scrape down the sides of the bowl and beat for one more minute.
Add the sugar to the butter mixture, ¼ cup at a time, beating 1 minute after each addition. Mix in the eggs one at a time until incorporated. Scrape down the sides of the bowl after each addition. Combine the buttermilk and the vanilla extract in a liquid measuring cup. With the mixer on low speed, add the dry ingredients alternately with the wet ingredients, beginning and ending with the dry ingredients and mixing just until incorporated. Scrape down the sides of the bowl and mix for 15 seconds longer.
Divide the batter between the prepared paper liners, filling each about 2/3 of the way full. Bake 18-22 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool in the pans 5-10 minutes, then transfer to a cooling rack to cool completely.
For the chocolate ganache icing:
4 oz. good quality dark chocolate, chopped into small pieces
1/3 C heavy cream
1 tbsp butter, cut into small pieces
Heat cream in a small pot until hot, but not boiling. Pour hot cream over chocolate pieces and stir until chocolate is melted. Stir in butter pieces until melted.