Transcribed from the 10/26/09 episode. Slow-churned European style butters have smaller butterfat crystals, which leads to smaller, finer bubbles and a finer texture in the finished cake, so splurge on the expensive butter for this! Be sure to use cake flour, not all-purpose; the finer particle size, the lower protein and the bleaching all lead to a better, more tender texture in the final cake. Substituting buttermilk for some of the eggs and butter lightens the cake, lowers the fat and calories, and adds a tangy note; Alton recommends whole buttermilk, not low-fat or non-fat. It's technically not a pound cake anymore, but we won't quibble with such good eats.