That question from reader Angela B. this afternoon, referring to the flour that RLB recommends for stick-proofing the bundt pan. In fact Rose’s top recommendation for greasing a baking pan is Baker’s joy, a top-of-the-line nonstick spray that has real flour in it. The trouble is that Baker’s Joy is frequently hard to find, and while me-too products are now being made by manufacturers like PAM, they tend to introduce off flavors and odors. That said, Rose’s #2 recommendation is to brush the inside of the bundt pan with melted shortening, then apply a dusting of Wondra flour.
The reason for the Wondra? Because the particle size is so much smaller compared to a regular AP flour. That smaller size reduces sticking and, so Rose says, also helps make the cake’s crust shinier.