Yellow Butter Cupcakes with Buttercream Frosting

Lots of February birthdays means lots of cupcakes!  This particular recipe made more cupcakes than I knew what to do with -- going forward I would probably halve the recipe.  I have been looking for a great recipe for buttercream frosting and this is IT -- in fact, my co-worker told me the frosting was almost better than a certain unnamed bakery in Chicago!  I took that as a huge compliment.

Yellow Butter Cupcakes 

source:  From Martha Stewart Living, February 2008
Makes 36 cupcakes

Ingredients:
3 cups cake flour (not self-rising), sifted
1 1/2 cups all-purpose flour
2 1/4 teaspoons baking powder
1 1/2 teaspoons coarse salt
3/4 teaspoon baking soda
9 ounces (2 sticks plus 2 tablespoons) unsalted butter, softened
2 1/4 cups sugar
5 large eggs plus 3 large yolks, room temperature
2 cups buttermilk, room temperature
2 teaspoons pure vanilla extract

Directions
1)  Preheat oven to 350 degrees. Line standard muffin tins with paper liners. Whisk dry ingredients in a large bowl. Cream butter and sugar with a mixer until light and fluffy. Add eggs, 1 at a time, beating after each addition.
2)  Reduce speed to low. Mix remaining wet ingredients in a bowl. Add dry ingredients to butter mixture in 3 additions, alternating with wet ingredients and ending with dry. Scrape sides of bowl. Divide batter among muffin cups, filling each full.
3)  Bake cupcakes until testers inserted into centers come out clean, about 20 minutes. Let cool in tins on wire racks.

Easy Vanilla Buttercream
source:  Annie's Eats, as found on The Way the Cookie Crumbles, originally from Cook’s Illustrated, April 2007

Ingredients:
20 tbsp. (2 ½ sticks) unsalted butter, softened
2 ½ cups confectioners’ sugar, sifted
1/8 tsp. salt
2 tsp. vanilla extract
2 tbsp. heavy cream

Directions: In a stand mixer fitted with the whisk attachment, beat butter at medium-high speed until smooth, about 20 seconds.  Add confectioners’ sugar and salt; beat at medium-low speed until most of the sugar is moistened, about 45 seconds.  Scrape down the bowl and beat at medium speed until mixture is fully combined, about 15 seconds.  Scrape bowl, add vanilla and heavy cream, and beat at medium speed until incorporated, about 10 seconds.  Then increase the speed to medium-high and beat until light and fluffy, about 4 minutes, scraping down bowl once or twice.