A tiger skin cake forms a distinctive pattern of light and dark patches as it bakes. Its current popularity seems to have expanded outward from China; I found a lot of Swiss-roll-style recipes that use it as an outer wrapper. Here, researchers look at how the wrinkled surface forms. The viscous batter quickly forms a solid skin on its surface, and, as the cake grows, the skin is forced to bend and wrinkle to accommodate the growth. Interestingly, the length-scale of the wrinkling pattern depends on the batter’s depth. For larger stripes, use a thicker layer of batter! (Image credit: K. Koutova et al.)
