I thought I'd seen just about everything that Luis Buñuel committed to film, but I found this while looking over the offerings in MOMA's Dalí: Painting and Film exhibition:
Menjant Garotes (Eating Sea Urchins). 1930. Spain. Directed by Luis Buñuel. While on location in Cadaqués to shoot scenes for L'Age d'or (1930), Buñuel made this home movie featuring Dalí's estranged father and stepmother in an intimate moment: dining alfresco on sea urchins, a local delicacy. The iconographic sea urchin also appears in Un Chien andalou (1929), as well as in Dalí's paintings of the late 1920s. Print courtesy Filmoteca de Catalunya-ICIC. 4 min.You won't find this surprisingly charming "home movie" at IMDB (at present), but you have a chance to see it tonight courtesy of Rooftop Films.
Spoilers: The film shows Mr. and Mrs. Dalí spending time together in a cliffside residence. One well-composed(!) shot shows them ascending a set of terraces, with unidentified people on the shore behind them. The climax comes with the meal of urchins, in which Mrs. Dalí pours what appears to be wine for Mr. Dalí, who indicates his approval of the culinary experience.