To me this dish typifies the late spring months. We use rump as we find that it usually has better flavour than the best end – and is significantly cheaper. The crushed Jersey Royals laced with olive oil complement it superbly.
Preheat the oven to 160°C/gas 3.
Season the lamb all over. Melt the butter with the olive oil in a frying pan and lightly colour the flesh side of the rumps in it. Turn over on to the skin side and finish roasting in the preheated oven for about 10 minutes for a medium-rare result. Allow to rest for about 10 minutes.
While the lamb is roasting and resting, cook the Jersey Royals in gently boiling salted water. Drain and peel while still warm. Put in a stainless-steel bowl, add a knob of butter, drizzle with olive oil, season and crush with a fork or old-fashioned potato masher, adding more butter and olive oil as you go. The aim is to create a homogeneous texture. The quantities of olive oil should be greater than the butter. The potatoes should be rich but also have hints of fruitiness from the oil. Keep warm.
While the potatoes are cooking, prepare the broad beans. Sweat the shallots in the butter until soft, add the wine and cook until syrupy. Add the cream, beans and marjoram. Season with salt and pepper and simmer for 5–10 minutes.
Serve the rested lamb with the roasting pan juices and the potatoes and broad beans.
© 2008 Anthony Demetre. All rights reserved.