Quick Recipe Version (TL;DR)
Quick Ingredients
- 1 bone-in leg of lamb (2.2 kg / 4.8 lb)
- 6 garlic cloves, halved; 8 rosemary sprigs
- 2 tbsp olive oil; 1 tbsp flaky sea salt; 1 tsp black pepper; zest of 1 lemon
- Potatoes: 1 kg (2.2 lb) floury potatoes; 120 ml (1/2 cup) goose fat; 1 tbsp semolina; salt
- Peas: 500 g (3.5 cups) frozen peas; 2 tbsp butter; 15 g mint leaves; 1 tbsp lemon juice; 1 tsp sugar
- Gravy: 150 ml red wine; 500 ml stock; 1 tbsp flour; 1 tsp Dijon; 1 tsp redcurrant jelly
- Mint sauce: 30 g mint; 2 tbsp sugar; 60 ml boiling water; 90 ml malt vinegar; pinch of salt
Do This
- 1) Preheat to 230°C/210°C fan (450°F/410°F). Stud lamb with garlic and rosemary; rub with oil, lemon zest, salt, and pepper. Rest 20 minutes.
- 2) Roast lamb 20 minutes, then lower to 180°C/160°C fan (355°F/320°F) and roast 1 hour 15 minutes, to 57°C/135°F internal for medium-rare.
- 3) Parboil potatoes 10 minutes; steam-dry, toss with semolina. Heat goose fat in a tray, add potatoes, and roast on a lower shelf 30 minutes.
- 4) Mix mint sauce: dissolve sugar in boiling water, add vinegar, mint, and salt. Steep 10 minutes.
- 5) Rest lamb 30 minutes, tented. Turn oven up to 220°C/200°C fan (425°F/390°F) and crisp potatoes 20–25 minutes.
- 6) Make gravy in the lamb pan with wine, flour, stock, mustard, and jelly; simmer 6–8 minutes until glossy.
- 7) Warm peas with butter, mint, lemon, and sugar 5 minutes. Carve lamb; serve with potatoes, peas, gravy, and mint sauce.
Why You’ll Love This Recipe
- Classic Sunday roast flavors: garlicky rosemary lamb, shatteringly crisp goose-fat potatoes, and fresh minted peas.
- A dependable timeline: everything lands hot on the table while the lamb rests.
- Pan gravy built from the roast drippings for deep, savory flavor.
- Bright, traditional mint sauce to cut through the richness.
Grocery List
- Produce: Leg of lamb, garlic, fresh rosemary, lemons, floury potatoes, fresh mint, frozen peas.
- Dairy: Unsalted butter.
- Pantry: Goose fat, olive oil, flaky sea salt, black pepper, semolina (or all-purpose flour), red wine, beef or lamb stock, Dijon mustard, redcurrant jelly, caster sugar, malt vinegar.
Full Ingredients
Garlic & Rosemary Roast Leg of Lamb
- 1 bone-in leg of lamb (about 2.2 kg / 4.8 lb)
- 6 garlic cloves, halved lengthwise
- 8 sprigs fresh rosemary (needles stripped; keep a couple of sprigs whole for the pan)
- 2 tbsp olive oil
- 1 tbsp flaky sea salt
- 1 tsp freshly ground black pepper
- Finely grated zest of 1 lemon
Goose-Fat Roast Potatoes
- 1 kg (2.2 lb) floury potatoes (Maris Piper, King Edward, or Yukon Gold), peeled and cut into 5 cm (2 in) chunks
- 120 ml (1/2 cup) goose fat
- 1 tbsp semolina (or 1 tbsp all-purpose flour)
- 1 tsp fine salt (for boiling water), plus 1–1.5 tsp flaky salt for finishing
- 2 garlic cloves, lightly crushed
- 2 sprigs rosemary
Classic Mint Sauce
- 30 g fresh mint leaves (about 1 cup packed), very finely chopped
- 2 tbsp caster sugar
- 60 ml (1/4 cup) boiling water
- 90 ml (6 tbsp) malt vinegar (or white wine vinegar)
- Pinch of salt
Pan Gravy
- 150 ml (2/3 cup) dry red wine
- 500 ml (2 cups) hot beef or lamb stock
- 1 tbsp all-purpose flour (or 1 tbsp cornstarch mixed with 2 tbsp water for a slurry)
- 1 tsp Dijon mustard
- 1 tsp redcurrant jelly (or 1 tsp honey)
- Roasting pan drippings and any caramelized bits
Minted Peas
- 500 g (3.5 cups) frozen peas
- 25 g (2 tbsp) unsalted butter
- 15 g fresh mint leaves (about 1 cup loosely packed), finely chopped
- 1 tbsp lemon juice
- 1 tsp sugar
- Salt and black pepper, to taste
Step-by-Step Instructions
Step 1: Prep the lamb and preheat
Take the lamb out of the fridge 30 minutes before cooking. Preheat the oven to 230°C/210°C fan (450°F/410°F). Using a small sharp knife, make about 24 shallow slits (2 cm / 3/4 in deep) all over the lamb. Push a sliver of garlic and a pinch of rosemary needles into each slit. Rub the lamb with olive oil, lemon zest, salt, and pepper. Place on a rack set inside a sturdy roasting tin, add a couple of whole rosemary sprigs to the tin, and let the lamb stand while the oven heats (about 20 minutes).
Step 2: Start the roast hot
Roast the lamb at 230°C/210°C fan (450°F/410°F) for 20 minutes to begin browning and render the surface fat. This high-heat blast builds flavor and color you’ll taste in the gravy later.
Step 3: Parboil and start the potatoes
While the lamb’s initial roast is underway, put the potatoes in a large pot of cold water with 1 tsp fine salt. Bring to a boil and cook for 10 minutes until the edges just turn tender. Drain well, then shake the pot with the lid on to rough up the edges. Sprinkle over the semolina and shake again until lightly coated.
Place a large roasting tray with the goose fat, crushed garlic, and rosemary into the oven for 5 minutes to heat until shimmering. Carefully add the potatoes to the hot fat (they should sizzle), turn to coat, and place the tray on a lower shelf under the lamb. When the lamb oven temperature drops in the next step, keep the potatoes roasting for 30 minutes, turning once.
Step 4: Make the classic mint sauce
In a small bowl, dissolve the sugar in the boiling water. Stir in the vinegar and a pinch of salt, then add the finely chopped mint. Let it steep for at least 10 minutes to turn vibrant green and fragrant. Taste and adjust sweetness or acidity to your liking.
Step 5: Lower the heat and finish the lamb
Reduce the oven to 180°C/160°C fan (355°F/320°F). Continue roasting the lamb for 1 hour 15 minutes to reach medium-rare. Use a probe thermometer inserted into the thickest part (not touching bone): pull the lamb at 57°C/135°F for medium-rare, 63°C/145°F for medium. Transfer the lamb to a warm platter, tent loosely with foil, and rest for 30 minutes. Pour off (and reserve) all but about 2 tbsp fat from the roasting tin; keep the tin for the gravy.
Step 6: Crisp the potatoes while the lamb rests
Increase the oven to 220°C/200°C fan (425°F/390°F). Toss the par-roasted potatoes in their tray and roast for a further 20–25 minutes until deeply golden with glassy-crisp edges. Sprinkle with flaky salt to finish.
Step 7: Make the pan gravy
Set the lamb roasting tin over medium heat on the hob. If the fond is very dark, splash in 2 tbsp water and scrape gently. Sprinkle in the flour and cook for 30 seconds, then pour in the red wine, scraping up all the browned bits. Simmer 1–2 minutes to reduce slightly. Add the hot stock, Dijon, and redcurrant jelly. Simmer 6–8 minutes, stirring, until glossy and spoon-coating. Strain into a warm jug and season to taste.
Step 8: Cook the minted peas and serve
In a saucepan over medium heat, melt the butter. Add the peas with 1 tbsp water, a pinch of salt, and the sugar. Cook 3–4 minutes until hot and tender. Stir in the chopped mint and lemon juice; season with pepper.
Carve the lamb across the grain into thick slices. Serve with the goose-fat roast potatoes, minted peas, a pool of pan gravy, and a bright spoon of mint sauce.
Pro Tips
- Timing formula: After the initial 20-minute high-heat roast, plan about 15 minutes per 500 g (1.1 lb) at 180°C/160°C fan (355°F/320°F) for medium-rare. Always verify with a thermometer.
- Target temps: Rare 52°C/125°F; medium-rare 57°C/135°F; medium 63°C/145°F; medium-well 68°C/155°F. Rest 30 minutes for juicier slices.
- Extra-crisp potatoes: Steam-dry after draining, use semolina for a rough surface, and preheat the goose fat until it shimmers.
- Clean gravy flavor: If drippings start to scorch, add a splash of water to the pan during roasting to prevent burning.
- Mint sauce brightness: Add a pinch more sugar if your vinegar is sharp; aim for a balanced sweet-tart snap.
Variations
- Anchovy-rosemary rub: Mash 3 anchovy fillets with the garlic and rosemary for deep savory flavor (it won’t taste fishy).
- Herb crust: Brush lamb with 2 tsp Dijon, then pat on 1/2 cup fresh breadcrumbs mixed with chopped parsley and olive oil for the final 20 minutes.
- Duck-fat or olive-oil potatoes: Swap goose fat for duck fat (ultra-crisp) or extra-virgin olive oil (lighter, still delicious).
Storage & Make-Ahead
Leftover lamb keeps 3–4 days chilled; slice and reheat gently with a splash of stock, or serve cold in salads and sandwiches. Freeze sliced lamb up to 3 months (wrap well). Parboil potatoes earlier in the day, rough them, and refrigerate; roast from chilled, adding 5 minutes to crisp. Gravy can be made a day ahead; reheat and thin with stock. Mint sauce keeps 1 week in the fridge. Minted peas are best cooked just before serving but reheat well with a knob of butter.
Nutrition (per serving)
Approximate values: 850 kcal; 45 g protein; 35 g carbohydrates; 52 g fat; 16 g saturated fat; 3 g fiber; 1,250 mg sodium. Values will vary with portion size and drippings used.
