Roasted Lamb Bouchons with Tarragon golden and rich

1 In a saucepan, pour a little duck fat then roast the lamb bones for 2 minutes, add the diced carrots and onions, sweat for 5 minutes, moisten with cold water (about 2.1 qt (2 liters)) salt and pepper, add 1 bay leaf a little thyme and a little fresh or dried tarragon, then place your 8 potatoes, cover. Cook for 15 to 18 minutes.

2 Test the cooking by inserting a knife which should pierce them without resistance then drain them on a plate, degrease the broth then strain it through a chinois (sieve).

3 Cut your 2 fillets into 12 small corks 2.5 to 3 cm thick, wrap them with a little string then into the fridge.

4 While your potatoes are still hot, cut lengthwise a lid about 1.5 cm thick, then using a spoon, hollow out the flesh into a bowl being careful not to damage the shell.

5 Salt and pepper this pulp then add 2 large spoonfuls of duck fat and mash everything with a fork.

6 On a baking sheet, put a little coarse salt so your potatoes stand upright then in each potato fill halfway with your mash, the small cube of foie gras finally cover with the rest of your puree and place the lid on each, put in the oven at 120°(th4).

7 In a saucepan, sweat your minced shallot with a little olive oil then add your vinegar and about 15 tarragon leaves, when only a teaspoon remains pour 1.7 cups (40cl) of your lamb juice then reduce by more than half add a small teaspoon of starch just diluted in cold water, degrease then blend and keep warm.