Dinner

Slow-Cooked Harissa Lamb with Onion Gravy Recipe

ByHailey Reed November 1, 2025November 1, 2025

Introduction

This slow-cooked harissa lamb is a comforting, flavorful dish perfect for a special family meal. The tender, spiced meat pairs beautifully with a rich onion gravy that’s full of warmth and depth.

A large, well-cooked piece of meat with a dark, crispy, and slightly burnt crust sits in the center of a metal baking tray, surrounded by roasted onions that are soft and deep brown with wrinkled skin. The meat has a long bone sticking out from the top left with charred bits on top, and the tray holds a rich, oily, dark reddish-brown sauce pooling around the edges. A large silver spoon is placed inside the tray on the left side, partly submerged in the sauce. The tray is placed on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Ingredients

2kg whole leg of lamb on the bone
10 red onions, cut in half
300ml chicken stock
4 tbsp chopped coriander
20 dried chillies
6 garlic cloves, grated
100ml olive oil
2 tsp ground coriander
2 tsp ground cumin
2 tsp caraway seeds
2 tsp smoked paprika
2 tbsp red wine vinegar

Instructions

Step 1: Place the dried chillies in a heatproof bowl and cover with just enough boiling water to submerge. Cover the bowl and leave to cool. Once cool, drain the chillies, reserving the soaking water. Remove any stalks and pat dry with kitchen paper.
Step 2: Put the chillies, garlic, 1 tsp salt, olive oil, ground coriander, cumin, caraway seeds, smoked paprika, and red wine vinegar into a food processor. Blitz to a smooth purée, adding some of the reserved water if needed to loosen the mixture. This is your harissa paste, which can be refrigerated for up to a month.
Step 3: Make 15 cuts, about 3-5cm long, all over the lamb leg. Reserve 1 tbsp of the harissa paste and rub the remainder thoroughly over the lamb, pushing some into the cuts.
Step 4: Scatter the halved red onions in a large roasting tin and place the lamb on top. Let it sit at room temperature for 1 hour, or cover and refrigerate overnight for deeper flavor.
Step 5: Preheat the oven to 160°C (140°C fan) or gas mark 2. Roast the lamb for 4 to 5 hours, until the meat is fork-tender and falling from the bone.
Step 6: Remove the lamb from the roasting tin and place on a serving plate or board. If your roasting tin is ovenproof, pour in the chicken stock directly; if not, transfer the onions and juices into a saucepan. Bring to a boil, scraping up any browned bits, and reduce the liquid by about one-third to create a thick, flavorful onion gravy.
Step 7: Stir the reserved 1 tbsp harissa paste and chopped coriander into the gravy. Serve the lamb hot with the spiced onion gravy spooned over.

Tips & Variations

For a milder version, reduce the number of dried chillies or remove the seeds before soaking.
Use lamb shoulder instead of leg for a slightly fattier, more succulent result.
Leftovers make fantastic sandwiches or wraps with some fresh salad and yogurt.

Storage

Store any leftover lamb and gravy in an airtight container in the refrigerator for up to 3 days. Reheat gently on the stovetop or in the oven to keep the meat tender. The harissa paste will keep separately in the fridge for up to a month.