1Preheat the oven to 350°F (180°C). Place the lamb, pig’s trotters, and oil in a deep baking dish covered with buttered foil or a Dutch oven covered with its lid. Cover the meats with all the vegetables, the thyme, and the garlic. Sprinkle with the salt and pepper, and pour in the wine. Add water to barely cover the meat.
2Cover with a sheet of buttered aluminum foil and place in the oven. Bake for 3 1/2 to 4 hours, or until the trotters are easily pierced with a fork and the lamb is tender enough to shred. Check from time to time and add more water as needed to maintain the original level.
3While the meats are cooking, make the sauce. Pour the stock into a small pot, bring to a simmer over high heat, and simmer until reduced by one-third. Stir in the mustard, butter, vinegar, gherkins, capers, shallot, tarragon, pepper, and lardons; reduce the heat to low, and cook for 5 minutes to blend the flavors. Taste and adjust the seasoning, adding more vinegar if you want a bit more bite. Remove from the heat and let cool before serving.
