Roast lamb loin wrapped in prosciutto

What cut of lamb is cannon?

Lamb loin is also known as cannon of lamb, one half or fillet from the saddle of lamb. It is the choicest cut of lean, almost transparent meat, sometimes cut with the mini fillet attached. That’s a bonus, because that thin, inconspicuous fillet is like chicken oysters: the morsel of deliciousness.

Lamb loin or cannon is the eye of glorious loin chops or the double-whammy Barnsley chops (which always remind me, graphically, of female reproductive organs in cross-section).

It isn’t very often you can buy it off even the butcher’s shelf, as sensibly, butchers prefer to cut the saddle across into steaks, rather than dissect the loin and be left with bone, fat and tendons. But if you place a special order with your friendly butcher, I’m sure they’ll manage to procure it for you – at a steep price.

Ways of cooking lamb loin

Better not waste such expensive meat in that case! But there is only one cardinal mistake you can commit: overcook it.

It is sometimes tricky to catch that particular moment between perfectly pink medium-rare and overdone. It still won’t be tough or dry, being such a fine cut, but it’s a shame not to have it at its best, and that is decidedly medium-rare.

To be honest, you can very simply sear it in the frying pan, turning and rolling it so it caramelises lightly on all sides. Then rest it and it’s done.

But it might put off those of your table mates who get a little squeamish if there is too sharp a line between browned and red in a crosscut of meat (‘It’s raw in the middle!’).

Searing is great but it won’t let the meat cook evenly throughout, even at the rare end of the spectrum: the middle will invariably be left not cooked very much, and might even not be warm.

Low temperature roasting

The way to handle it, which I have done often, is to cook the meat at a very low temperature. That method will give a result very close to sous-vide cooking but without the costly apparatus and the complex know-how.

It admittedly works best in electric ovens with fan (convection) as they are able to keep steady temperature and distribute the heat (the warmth!) evenly. I use my warming drawer for this purpose: it heats up to 80C/176F and keeps the temperature steadily.

But a decent oven will do the same, and the whole process gives you flexibility, as it is virtually impossible to overcook the meat like that, unless you keep it in for hours, obviously.

The only downside is aesthetical and olfactory: low-temp roasted meat does not look or smell terribly appetising. It lacks the Maillard reaction: the look and scent of caramelisation on the surface of meat protein.

The instinctive solution to remedy it is to sear the meat beforehand. It works, but during its time in the low-temperature oven the meat will lose the heat and spit it acquired in the frying pan. I like to do that exercise in reverse.

How to roast a perfect cannon of lamb?

Best cuts of meat need little seasoning but whoever wouldn’t like a little rosemary and thyme on their lamb? Rosemary needs to be chopped very finely. If you have a spice grinder or a coffee grinder dedicated to seeds and nuts, whiz the rosemary leaves in it briefly.

Tip: you can get rid of the smell and residue from the grinder by blitzing a couple of loads of bread in it.

So the paste made from ground together rosemary, thyme and garlic, with a little salt, will provide more than ample seasoning.

And then I wrap the whole cannon in slices of prosciutto, not only because it’s gorgeous but to cheat a little with the Maillard discussed above. Prosciutto will only need a lick of heat to caramelise attractively, and it will protect the lamb inside from being cooked.

Whole or half cannon per person?

This is one of those situations where the best portion allocation is three people sharing two fillets. Or six people sharing four, as threesomes hardly ever happen to eat together (or maybe I’m old-fashioned?). So if you’re feeding two or four it’s a dilemma: go short or have leftovers.

In case you are serving lots of sides and fillers, go for the former. And the latter is by no means a waste as cold roast cannon is as good as cold beef and you’ll be scoffing it happily in a sandwich on the following day.

What to serve with cannon of lamb?

We’re talking about posh dinners, so I’d say potatoes dauphinoise would be fitting, plus some nicely presented vegetables, fondant carrots perhaps or green beans with Parmesan cream.

But if you’d rather go for a salad on the side, courgette ribbons are a good suggestion.

More lamb recipes

Lamb breast is an underrated cut which, cooked well, can be presented as a fancy dish. Lamb breast with grapes for instance, rolled with herbs and roasted, is absolutely great.

You’d like to stick with the classic lamb rack for your dinner with friends? How about grilled with pineapple? Or you can cook the cutlets coated in Parmesan crust.

Then there are the traditional recipes: the roast leg, the roast shoulder, the rack, the grilled neck fillet…