Thank you Mark Bittman for successful popovers (aka Beefless Yorkshire Pudding) this Christmas! Christmas 2007 will go down in history as the year the popovers just didn't pop, puff, or poof. My sad hockey puck popovers were endlessly mocked by my British relatives and left me reluctant to repeat the experience despite perfect popovers in years prior. Mark Bittman gave me the courage to try again. This year I made sure all ingredients were room temperature, didn't over-beat the eggs, and let the butter heat up with the pan in the oven. I did notice that the second batch of popovers was even better than the first. . . I think resting the batter and having a very hot popover pan may matter more than the temperature of the oven which varied greatly during the second batch.

More experiments may be needed.