For the seasoning paste:
* 1 bushy sprig of fresh rosemary (you can substitute 1 tablespoon dried rosemary, but fresh really is preferable)
* 1 organic lemon
* 10 filets of anchovies packed in olive oil, drained
* 3 cloves garlic, peeled, germ removed if any
* 2 teaspoons whole mustard seeds
* A few generous grinds of black pepper
* 2 teaspoons balsamic vinegar
* 2 teaspoons olive oil

For the meat:
* 2.2 kg (5 pounds) bone-in shoulder of lamb (depending on the size of the animal, this may amount to one large shoulder, or 1 1/2 small shoulders)
* 8 small ripe tomatoes, about 650g (1 1/3 pounds)
* 4 cloves garlic, still in the last layer of their papery sheath