Lamb Sweetbreads with Chile Caribe and Posole

I first tasted lamb sweetbreads in the early 1980s at St. Estèphe, the pioneering contemporary-Southwestern restaurant in Manhattan Beach, just south of Los Angeles. Chef John Sedlar used to serve them there in a New Mexican chile sauce with hominy (posole), in pretty little copper cassolettes, and they were memorably good. I once tried to create a lamb sweetbread dish of my own—something with tomatillos and pearl onions, if I recall correctly. Assuming that the sweetbreads had to be blanch