Spicy Black Bean Burgers

Like all ground-meat dishes, burgers benefit from some filler. Fillers add flavor and creaminess, and because most contain some starch, and starch absorbs moisture, burgers containing a purée of beans, or bread or cereal, keep their juices better than plain old unadulterated naked ground beef alone. In this burger, the filler is bean dip, which adds a little heat and the fragrance of cumin as well as moisture.