Part 2/9:
Begin with a 9-inch, 3-inch deep cake pan, generously buttered (preferably with softened butter, which adheres better). The bottom of the pan, which becomes the top after inversion, gets a layer of fresh rhubarb slices cut diagonally into quarter-inch pieces. These are sprinkled with three-quarters of a cup of sugar to coax out their juices, softening them slightly and ensuring a moist, flavorful base.