Roast Lamb With Laver Sauce

Roast Lamb with Laver Sauce (Welsh-style)

A traditional Welsh Sunday-roast centrepiece: a leg of lamb roasted until blushing pink at the bone, served with a silky green sauce made from laver seaweed, butter and lemon. Canned laver purée keeps the recipe faithful and achievable in any home kitchen.

Prep

20 min

Cook

80 min

Total

100 min

Serves

6

Difficulty

Medium

Recipe ingredients

• •1800 g (4 lb) bone-in leg of lamb, shank end, fat cap left on
• •2 tbsp olive oil
• •4 g (1 tsp) sea salt, coarse
• •5 g (1 tsp) black pepper, freshly ground
• •6 cloves garlic, skin on, smashed
• •2 sprigs fresh rosemary
• •6 sprigs fresh thyme
• •200 g (7 oz) canned laver seaweed (puree), puréed laver; this is the authentic Welsh product available in jars/tins
• •60 g (¼ cup) unsalted butter, cut into cubes
• •10 g (1 tbsp) cornflour (cornstarch), to thicken if needed
• •15 ml (1 tbsp) lemon juice, freshly squeezed
• •150 ml (⅔ cup) hot lamb or chicken stock, to loosen the sauce

Steps

1. 1 Take the lamb out of the fridge 45–60 minutes before cooking so it loses the chill. Pat the skin and fat dry with paper towels.
2. 2 Preheat the oven to 220°C / 425°F (200°C / 400°F fan). Rub the lamb all over with olive oil, then season generously with sea salt and black pepper.
3. 3 Place the smashed garlic, rosemary and thyme in a small roasting tin and lay the lamb on top, fat side up. Roast at 220°C / 425°F for 20 minutes to colour the fat cap.
4. 4 Reduce the oven to 170°C / 340°F (150°C / 300°F fan) and continue to roast. Calculate roughly 25–28 minutes per 500 g / 1 lb for medium (rosé at the bone). For a 1.8 kg / 4 lb leg, this is about 90–100 minutes total.
5. 5 Use a meat thermometer to check doneness in the thickest part, avoiding bone: pull at 50–52°C / 122–125°F for medium-rare, 60°C / 140°F for medium. The temperature will rise 3–5°C / 5–9°F while resting.
6. 6 Transfer the lamb to a warm board, cover loosely with foil, and rest for at least 20 minutes (up to 30). Pour the pan juices into a jug and skim off the fat.
7. 7 While the lamb rests, make the laver sauce: pour the canned laver purée into a small saucepan with the hot stock and whisk over medium heat until smooth and hot.
8. 8 Whisk in the butter a few cubes at a time to emulsify. Stir in the lemon juice. If the sauce looks loose, whisk the cornflour with 1 tbsp cold water and stir it in; simmer 1 minute to thicken. It should coat the back of a spoon.
9. 9 Carve the lamb into thick slices against the grain. Serve hot with the warm laver sauce spooned over or alongside, and a little of the resting juices.
10. 10 SAFETY - doneness: lamb is safe eaten at 63°C / 145°F internal (medium-rare carries a low risk for whole cuts of muscle meat from a reputable butcher). Cook to at least 71°C / 160°F if you are pregnant, immunocompromised or serving very young children.