I have a confession. On this cake, I didn't stick completely to Martha's recipe, in two ways. The first way was I wanted to give the cake a little taste boost and used an actual vanilla bean (it was hard to find: Whole Foods) instead of vanilla extract. It definetely paid off.
The second change was the website recipe called for the egg white frosting (holy smokes. Again! Really! That frosting is foul!) I made my own go-to chocolate frosting. And, it also paid off in a big way. My poor 6 year old (sarcasm). I said "A" do you want some cake? No. I replied, "I put my frosting on it." She quickly said, "OK then." It is sad when my sweet tooth kid will turn down cake because of the last few weeks experience with the Martha Frosting. Whoo! ANYWAY, the chocolate frosting and the vanilla tasting cake was OUT OF THE PARK. The cake was gone by Wednesday.
1 Cup (2 sticks) Unsalted Butter, room temperature, plus more for pans