As an artist, Caitlin Freeman found her calling in cake.

She bakes at the cafe in the San Francisco Museum of Modern Art, where the most popular item is a dessert inspired by the art of Piet Mondrian. It features geometric blocks of white velvet cake, colored red, blue and yellow, stacked together and “glued” with chocolate. It takes two days to prepare, according to her new cookbook, Modern Art Desserts.