The NY Times article I linked above says that belly is just the hip new word for breast. But "breast" isn't really the right term, because this boneless slab also contains the flank, and all of the flap that covers the loin, stretching the length of the torso from scapula to pelvis. On a cow you would call this the plate, flank and deckle.
This meat is full of sinew. Usually we slice this into little squares and then boil the life out of them to make rich, chunky sauces. But this slab I trussed.
The flavor of lamb is communicated almost entirely through its fat, and this belly, heavily streaked, is naturally very strong, and effortlessly rich. I wanted a preparation that would cut into those elements with freshness and acidity. Instead of browning the meat, I just nestled it into a pot with white wine, and added lamb stock to cover. In went thyme, red onion, smashed garlic cloves, and sliced Castelvetrano olives.
Three hours in the oven was just right to allow the belly to break down without completely falling apart. To finish the dish, I reduced the jus down with a lump of butter, and then glazed a disc of belly.
We'll be serving these family style over the next night or two. Each belly weighed about two pounds before cooking, and should serve four.