Ingredients

a small shallot

　　white wine vinegar – 3 tablespoons

　　black peppercorns – 6

　　mint leaves – 2 tablespoons, stems reserved

　　egg yolks – 2

　　butter – 10 tablespoons (150g), soft, almost melted

　　

Step 1

Peel and finely chop the shallot, then put it in a small saucepan with the vinegar, peppercorns, and the stems from the mint leaves. Bring to a boil and watch it while it reduces to a tablespoon or so. Put the egg yolks into a heatproof bowl and place it over a pan of very lightly boiling water. The bowl should sit snugly in the top of the pan. Whisk the reduced vinegar into the egg yolks, holding back the debris in the pan, then slowly add the butter a little at a time, whisking almost constantly until it is thick and velvety.

　　

Step 2

Coarsely chop the mint leaves and stir them in, then taste for salt and pepper. Check that the sauce doesn’t get too hot. It will keep warm until the lamb is cooked, with the occasional whisk, over the pan of water with the heat off.

　　Tender