This dish is made interesting by contrasts. It is, substantially, a sandwich of firmly braised sweetbread between crisp potato galettes. The flavours are a balance of balsamic vinegar, caramelised shallots, and good olive oil. No one flavour should predominate, and balsamic vinegar, especially a really good old one, will sharpen and enhance the delicate flavour of sweetbreads without upstaging it.
It is not difficult to make but I recommend that you prepare the stock a day or two in