This high protein rosemary garlic leg of lamb is the main course to make when you want a proper Thanksgiving centrepiece without cooking a whole turkey. A leg of lamb gets a rosemary, garlic, lemon and Dijon rub, roasts slowly at 200°C, then rests before slicing — 40g of protein per serving, a golden crust, a pink centre, and a roast that carves beautifully at the table.
The trick is the thermometer, not the clock. Lamb goes from perfect to overdone in a few minutes, so pull it out a few degrees early and let the rest do the last bit of cooking. The rosemary and garlic do the rest of the work: lemon brightens the richness, Dijon helps the rub stick, and the olive oil helps the crust turn golden.
Why you’ll love it
- 40g protein per serving, about 430 calories
- A proper Thanksgiving centrepiece that serves 6 — no whole turkey needed
- Rosemary-garlic crust and a pink centre, mostly hands-off in the oven
- Leftovers slice beautifully for sandwiches and salads the next day
Ingredients
- 1.8 kg (about 4 lb) leg of lamb, bone-in or boneless, trimmed
- 6 garlic cloves, minced
- 3 tbsp fresh rosemary, finely chopped, plus sprigs to serve
- 2 tbsp olive oil
- 1 tbsp Dijon mustard
- 1 lemon, zested and juiced
- 1 tsp coarse sea salt
- 1 tsp black pepper, freshly ground
- 1 tsp dried oregano
Equipment used
- A stainless steel roasting pan with a rack, for roasting the lamb so the crust stays crisp
- An instant-read meat thermometer, for hitting medium-rare
- A sharp carving knife, for slicing the roast cleanly
- Kitchen twine (if boneless), for tying the roast so it cooks evenly
Instructions
- Take the leg of lamb out of the fridge 30 minutes before cooking and pat it dry with paper towels. If boneless, tie it with kitchen twine at 5 cm intervals so it holds an even shape. Score the fat in a shallow diamond pattern.
- Mix the garlic, rosemary, olive oil, Dijon mustard, lemon zest, lemon juice, salt, pepper and oregano into a thick paste.
- Rub the paste all over the leg of lamb and leave it for 15 minutes while the oven heats.
- Heat the oven to 200°C (400°F). Place the lamb on the rack in the roasting pan and roast for 1 hour 45 minutes to 1 hour 55 minutes, until an instant-read thermometer reads 57°C (135°F) in the thickest part for medium-rare.
- Rest the lamb on a board, tented loosely with foil, for 15 minutes. The temperature will rise a few degrees as it rests — this is part of the cooking, not a pause.
- Slice thinly against the grain and serve on a platter with rosemary sprigs, spooning the pan juices over the top.
Tips
- Use an instant-read thermometer — it is the only reliable way to hit medium-rare, and a roast this lean forgives nothing.
- Don’t skip the rest. Slicing too soon spills the juices onto the board instead of keeping them in the meat.
- A boneless leg cooks a little faster than bone-in, so start checking the temperature 15 minutes early.
- The lamb keeps 3 days in the fridge. Slice it cold and thin for sandwiches, or warm it gently in a low oven.
Estimated nutrition per serving
| Nutrient | Amount per serving |
|---|---|
| Calories | 430 |
| Protein | 40g |
| Carbohydrates | 3g |
| Fat | 24g |
These are estimated macros based on standard ingredient values, not lab-measured results.
More high-protein recipes to try
- High Protein Lamb Kebabs with Garlic Yogurt — 30g Protein
- Lamb Shepherd’s Pie with Greek Yogurt Mashed Potatoes — 35g Protein
- High Protein Thanksgiving Beef Tenderloin with Garlic Herb Crust
FAQ
Can I use a boneless leg of lamb? Yes — boneless is easier to carve and cooks a little faster, so start checking the temperature about 15 minutes early. Bone-in gives a slightly juicier roast, but the method and the rosemary-garlic rub are exactly the same.
Is this high protein rosemary garlic leg of lamb good for a small Thanksgiving? Yes. It is built for one: a 4 lb leg serves 6 generously, and it scales easily — a 6 lb leg serves 9 with the same method and about 20 extra minutes in the oven.
How do I know when it is done? Go by temperature: 57°C (135°F) for medium-rare, 63°C (145°F) for medium, 71°C (160°F) for well done. Pull the roast out 3 degrees early — it keeps cooking while it rests.
Can I make the rosemary-garlic rub ahead? Yes. Mix the paste a day ahead and keep it covered in the fridge, then rub it on the lamb an hour before cooking so the flavours have time to sink in.
High Protein Rosemary Garlic Leg of Lamb for a Small Thanksgiving — 40g Protein
Equipment
- A stainless steel roasting pan with a rack for roasting the lamb so the crust stays crisp
- An instant-read meat thermometer for hitting medium-rare
- A sharp carving knife for slicing the roast cleanly
- Kitchen twine (if boneless) for tying the roast so it cooks evenly
Ingredients
- 1.8 kg leg of lamb about 4 lb, bone-in or boneless, trimmed
- 6 garlic cloves minced
- 3 tbsp fresh rosemary finely chopped, plus sprigs to serve
- 2 tbsp olive oil
- 1 tbsp Dijon mustard
- 1 lemon zested and juiced
- 1 tsp coarse sea salt
- 1 tsp black pepper freshly ground
- 1 tsp dried oregano
Instructions
- Take the leg of lamb out of the fridge 30 minutes before cooking and pat it dry with paper towels. If boneless, tie it with kitchen twine at 5 cm intervals so it holds an even shape. Score the fat in a shallow diamond pattern.
- Mix the garlic, rosemary, olive oil, Dijon mustard, lemon zest, lemon juice, salt, pepper and oregano into a thick paste.
- Rub the paste all over the leg of lamb and leave it for 15 minutes while the oven heats.
- Heat the oven to 200°C (400°F). Place the lamb on the rack in the roasting pan and roast for 1 hour 45 minutes to 1 hour 55 minutes, until an instant-read thermometer reads 57°C (135°F) in the thickest part for medium-rare.
- Rest the lamb on a board, tented loosely with foil, for 15 minutes. The temperature will rise a few degrees as it rests — this is part of the cooking, not a pause.
- Slice thinly against the grain and serve on a platter with rosemary sprigs, spooning the pan juices over the top.
Notes
Instant Read Meat Thermometer
the only reliable way to hit medium-rare on a lean roast like leg of lamb.
Stainless Steel Roasting Pan with Rack
keeps the roast out of its own juices so the rosemary-garlic crust stays crisp.
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