Favorite Butter Cupcakes

Directions

1. 1
   In a medium bowl, sift together the flours, baking powder, baking soda and salt.
2. 2
   In the bowl of a stand mixer using the paddle attachment, or in a large bowl using a hand mixer, cream together the butter and sugar at medium speed until the mixture is light and airy, about 5 minutes.
3. 3
   Scrape the sides as needed for even mixing.
4. 4
   With the mixer running, mix in the whole eggs, then the yolks, one at a time, until fully incorporated.
5. 5
   Mix in the vanilla until just combined.
6. 6
   Mix in the combined dry ingredients and sour cream, alternating between the two (one-third of the dry, then half of the sour cream, in stages) until both are thoroughly combined, being careful not to over-beat.
7. 7
   Evenly spoon the batter into 20 lined cupcake pans; the batter should fill each liner two-thirds to three-fourths full.
8. 8
   Bake the cupcakes, one pan at a time and in the center of the oven, until the cupcakes have risen and a toothpick inserted into the center comes out clean, 15 to 20 minutes.
9. 9
   Rotate the pan halfway through for even baking.
10. 10
    Remove the pan to a rack to cool before frosting the cupcakes.
11. 11
    The cupcakes are best eaten the same day they are made or frozen as soon as they are cool.