Sweet marinade

Gratin potato
Photograph: Bryan O'Brien

FOOD: Well-cooked lamb with seasoned gratin potatoes is an ideal pairing for a Sunday roast, writes Domini Kemp

THE SMELL of meat roasting is pretty darned amazing. Despite the fact that I am partial to pink lamb and medium-rare steaks, there is something fabulous about the charred, salty caramelised outside of a piece of roast meat and that's because colour equals flavour. Although we've often been told that "searing" meat helps keep all the juices in, unfortunately science now tells us that this is hooey. Meat loses water when seared in a pan at a high heat. The "crust" that forms does not help keep the juices in, but instead gives an incredibly tasty flavour that occurs because of a complex chemical transformation called the "Maillard" reaction.

Anyway, without getting all techy and sciencey, suffice to say that good colour can only be achieved by high heat, or else a lower heat and something sugary that will caramelise - in this case the honey.

Loin of lamb is very expensive, but definitely worth it for a special occasion. In this recipe, I have used 500g to feed four people, which may seem a little stingy, but if the loin has been well trimmed, there will be very little waste. If you are worried about not being able to satisfy big appetites then definitely serve with the gratin potatoes. This marinade can also be used for roast leg of lamb.

Roast spiced loin of lamb

50ml olive oil
50ml Balsamic vinegar
1 teaspoon cumin seed
1 teaspoon fennel seed
1 teaspoon mustard seed
1 tablespoon honey
2 cloves garlic, peeled and crushed
few sprigs thyme
salt and black pepper
500g loin of lamb

Preheat the oven to 200 degrees/gas six. Put all the ingredients for the marinade, except the salt, in a large bowl or gratin dish and mix well. Add the lamb, cover it and marinate, overnight if possible, but an hour will do.

Before cooking the lamb, bring it to room temperature by taking it out of the fridge and leaving it out for about 15 minutes. Heat a large frying pan until it is very hot. Season the lamb while it is still in the marinade, and carefully place the loin in the pan. Quickly sear on all sides until it is well-browned. Pour in the remaining marinade, transfer to the gratin dish and cook in the oven for a further eight minutes.

Allow the meat to rest by removing from the oven, covering it with foil and leaving it for at least five minutes, before slicing and serving. Do let the meat rest or else it will look well-done and dried out. Resting gives the meat a chance to re-distribute the juices evenly.

Gratin potatoes (serves 4-6)

I never fail to get loads of compliments for this version of Pommes Dauphinoise. The secret is simple. I cook the potato and cream mixture in a large saucepan for about 10 minutes before transferring it to a gratin dish. This really helps ensure accurate seasoning, as you can taste the seasoned mixture before it goes in the oven, as opposed to layering up spuds, cream, salt and pepper, not really knowing what it tastes like.

Traditionally, Pommes Dauphinoise is made by rubbing a gratin dish with some butter and a clove of garlic, followed by layers of spuds, cream, salt, and perhaps a little nutmeg. I prefer to do mine with less cream (milk instead) and loads more garlic. If serving it with lamb, I wouldn't top it with cheese, but if you're serving this as a main dish for a veggie mid-week supper, then by all means do top it with a type of cheese that goes all brown and crispy.

Knob butter
1kg potatoes (all purpose, large) washed and thinly sliced (leave the skins on) 300ml cream
300ml milk
salt and pepper
2-3 cloves garlic, peeled and crushed
200g grated cheese, optional

Preheat the oven to 180 degrees/gas four. Rub the gratin dish with butter. Put the sliced potatoes, cream, milk and garlic in a large saucepan and gently bring to the boil. There should be enough liquid to just cover the potatoes. If not, it top up by adding equal quantities of milk and cream, or a splash of water.

Cook the potatoes by gently simmering the mixture for about five to 10 minutes. But don't abandon this mixture, as the cream and milk burns very easily if you don't stir it occasionally, or have it on too high a heat. Taste the cream mixture and make sure it's salty enough. Remove from the heat, scoop out the spuds and layer them fairly neatly in a gratin dish. Pour the creamy liquid on top. Make sure there is enough to just cover the spuds. Top with grated cheese, if using, and bake for 35-40 minutes. Stick a knife into the centre to check that the potatoes are very soft - you should not feel anything remotely crunchy. If you do, cook for another 15-20 minutes. Remove the gratin from the oven and let it sit for about five minutes before serving.

© 2008 The Irish Times

This article appears in the print edition of the Irish Times