Slow-Roasted Lamb with Rosemary and Parkland Mint Sauce

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · ·

Succulent slow-roasted lamb infused with rosemary, paired with a refreshing mint sauce reminiscent of London's royal gardens. This british-inspired lamb ready in about 170 minutes pairs leg of lamb, fresh rosemary sprigs, garlic cloves, sliced for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 480 calories and feeds 6, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart.

Prep: 20 min Cook: 150 min Serves 6 British cuisine 480 cal/serving
Plan a meal with the AI →

Ingredients

Instructions

  1. Step 1: Preheat oven to 325°F. Using a sharp knife, make 12 small incisions all over the 4 lb leg of lamb and insert 6 sliced garlic cloves and 4 fresh rosemary sprigs evenly.
  2. Step 2: Rub the lamb with 3 tbsp olive oil, then season generously with 2 tsp salt and 1 tsp black pepper. Place in a roasting pan and roast for 2 to 2.5 hours until an internal temperature of 135°F for medium-rare is reached.
  3. Step 3: While the lamb cooks, prepare the mint sauce by finely chopping 1/2 cup fresh mint leaves and combining them with 2 tbsp white wine vinegar, 1 tsp sugar, and 1/4 cup water in a small bowl. Stir until sugar dissolves and set aside.
  4. Step 4: Remove the lamb from the oven and cover loosely with foil. Let rest for 15 minutes before slicing. Serve with the mint sauce drizzled on the side for a classic pairing that evokes the tranquility of London's royal parks.

Frequently asked questions

How long does Slow-Roasted Lamb with Rosemary and Parkland Mint Sauce take to make?

Total time is about 170 minutes (20 min prep + 150 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Slow-Roasted Lamb with Rosemary and Parkland Mint Sauce?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep leg of lamb from drying out.

Can I substitute ingredients in Slow-Roasted Lamb with Rosemary and Parkland Mint Sauce?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Slow-Roasted Lamb with Rosemary and Parkland Mint Sauce for a different number of people?

The recipe is written for 6 servings. Multiply each ingredient by (your serving target / 6). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

What goes well with Slow-Roasted Lamb with Rosemary and Parkland Mint Sauce?

British lamb like this pair well with a simple grain (rice, couscous, or crusty bread), a quick salad with acid (lemon vinaigrette, pickled onions), and a pan sauce or yogurt-based dip. Tap "Plan a meal with the AI" to get specific side suggestions.

Related recipes