Heat half the oil in a heavy casserole dish. Soften the shallots for 5 mins over a low heat in a large heavy-bottomed casserole. Sprinkle with the sugar and flour.
Stir for 30 seconds, then pour in the wine, stock and herbs. Bring to the boil and reduce by half over a low heat (approx. 20 mins).
Remove from the heat and add the butter in small pieces, stir and adjust the seasoning.
Meanwhile, heat a non-stick pan without oil on a high heat. Brush the steaks with the remaining oil and season. Fry for 6-8 mins on each side.
Serve piping hot, with the sauce, seasonal vegetables and new potatoes tossed in oil with rosemary and sea salt.
Remember to take the steaks out of the fridge 20 mins before cooking, to bring up to room temperature.
The lamb steaks can also be grilled or barbecued.