Classic Boneless Lamb Roast with Pan Gravy (The Sunday Roast Worth Making)

Name: Classic Lamb Roast Recipe with Gravy
Prep time: 20 min
Cook time: 60 min
Total time: 90 min
Ingredients: 7-8 lb boneless leg of lamb; 4 tablespoons olive oil (or avocado oil); 1½ teaspoons kosher salt; 1 teaspoon black pepper; 4 garlic cloves (minced); 1 tablespoon fresh rosemary (chopped); 2 tablespoons lemon juice; 1 large onion (thick wedges); 2 carrots (chunked); Fresh Rosemary; 4 garlic whole cloves; 1 cup low-sodium chicken broth; 2 tablespoons unsalted butter; 4 tablespoons all-purpose flour; 2 cups low-sodium chicken broth; ½ teaspoon salt; ½ teaspoon ground pepper

Sunday dinner just got a new standard. This is the classic roast lamb recipe with a pan gravy built from the drippings; it’s rich, silky, and the reason nobody pushes back from this table early.

Plate with slices of roast lamb topped with brown gravy, seasoned potato wedges, and a garnish of rosemary, with lemon wedges and sauce nearby.

In this recipe:

Most people avoid lamb because they’re afraid of overcooking it… or undercooking it… and serving something that tastes ‘gamey’. This recipe takes all of that off the table. First, we found a lamb company whose lamb tastes incredible every time, with none of the grassy, gamy flavor you think lamb is supposed to have (we link to it in the ingredients list so you can check it out for yourself).

Blast it at 425°F for 15 minutes to lock in the crust, drop the heat, and let the oven do the work until the center hits 135°F. A thermometer tells you exactly when to pull it. No guessing, no cutting in to check, no dry grey meat.

The pan gravy built from the drippings is the pro move; silky enough to coat every slice and smother your potatoes. Trust us, don’t skip the gravy. This is the recipe we use whether we’re cooking for six or sixteen. Master this once, and you own lamb forever.

Raw boneless leg of lamb on a baking sheet surrounded by bowls of chopped carrots, onions, garlic, butter, spices, salt, broth, olive oil, and a halved lemon on a beige surface.

🔪 Ingredients for classic Roast Lamb with Gravy

Boneless leg of lamb: Choose one that’s evenly thick. If untied, roll and tie it so it cooks evenly. We buy our lamb from Freedom Run Farm because it’s USDA-Certified American lamb with no gamey flavor and beautiful marbling.
Olive oil
Kosher salt & Freshly ground black pepper
Garlic: Use fresh.
Fresh rosemary: Chop fine so it sticks and doesn’t burn.
Fresh lemon juice

Roasting Bed

Onion & Carrots
Whole garlic cloves: Keep whole so they don’t burn. We’ve even been know to cut off the top 1/4 and use a whole heat of garlic
Fresh rosemary sprigs
Low-sodium chicken broth: Keeps the drippings from burning and becomes the gravy base.

Pan Gravy

Salt and pepper
Unsalted butter
All-purpose flour
Low-sodium chicken broth: Warm it a bit to prevent lumps.
Strained pan drippings

Equipment

Roasting pan with rack
Instant-read thermometer (a non-negotiable for perfect doneness)
Kitchen twine
Small saucepan
Fine mesh strainer

Choosing the Right Leg of Lamb

Bone-in vs boneless: Bone-in looks impressive, but boneless cooks more evenly and is easier to carve. For consistent slices from edge to center, a boneless leg of lamb is the smarter move.

Size, marbling, and thickness: Most legs run between 5 to 8 pounds. Plan on about ½ pound per person. Look for American lamb with light, even marbling and firm white fat. Thickness matters more than weight. An evenly shaped roast cooks better, while tapered ends overcook before the center is ready.

📝 How to Roast Boneless Leg of Lamb

Prep the oven. Set a rack in the lower-middle position and preheat to 425°F.
Make the paste. Mix olive oil, salt, pepper, garlic, rosemary, and lemon juice into a thick paste.
Season aggressively. Pat the lamb dry. Rub the paste all over and into any seams or folds. If the roast is unrolled, fold it and roll it into a tight cylinder, then tie it with twine every 1½ inches to guarantee even cooking.
Marinate. Refrigerate 2–24 hours. The longer the rest, the deeper the garlic-rosemary flavor. Let the lamb sit at room temp 20–30 minutes before roasting so it cooks evenly.
Build the roasting base. Scatter onion, carrots, whole garlic, and rosemary in the roasting pan. Pour in 1 cup of broth. Set the rack over the vegetables.
Start hot for color. Place the lamb seam-side down. Roast at 425°F for 15 minutes uncovered to build a browned crust, just when you’re roasting a prime rib.
Lower and finish. Reduce the heat to 400°F. Continue roasting until the center reaches:
- 130–135°F for medium-rare135–140°F for medium
Start checking early. Total time is usually 60–90 minutes, depending on thickness, not weight. If you’re unsure, here’s how to tell when lamb is done without guessing.
Rest properly. Transfer to a cutting board. Tent loosely with foil and rest 15–20 minutes. Internal temp will rise 5–10 degrees from carryover cooking.
Make the pan gravy.
- Melt butter over medium heat.
- Whisk in the flour and cook for 1–2 minutes, until pale golden and nutty-smelling.
- Slowly whisk in warm broth and strained pan juices.
- Simmer 3–5 minutes until thick enough to coat the back of a spoon.
- Season to taste.
Slice correctly. Snip the twine. Slice across the grain into ¼–½-inch slices for maximum tenderness.

A cooked roast lamb with several slices cut, garnished with lemon wedges and fresh herbs, on a serving platter next to seasoned roasted potatoes.

🔄 Substitutions & Variations

Shoulder instead of leg: Richer and slightly fattier. Roast a bit longer; still pull at temperature.
Herb swap: Add thyme or oregano with the rosemary. Or go for a rack of lamb and try our herb crusted rack of lamb.
Mustard boost: Add 1 tablespoon Dijon to the paste for sharper depth.
No flour gravy: Deglaze the pan with broth or white wine and reduce for a lighter jus and let it simmer to thicken.

💡 Meat Nerd Tips

Leg is lean; cook to temperature, not time. A boneless leg of lamb has far less internal fat than a shoulder. That means there’s less margin for error. Pull it at 130–135°F and let carryover do the rest. Cooking times are only a suggestion.
Dry the surface thoroughly. Pat the lamb dry before applying the herb paste. Surface moisture steams the meat and kills your crust.
Create even thickness before tying. If one end is thinner, fold it under before rolling and tying. A uniform cylinder cooks evenly and prevents dry edges. Use twine every 1½ inches to keep the roast compact, so heat penetrates evenly from edge to center.
Use a thermometer. Always. Guessing is how expensive lamb turns gray. An instant-read thermometer takes 5 seconds and saves the roast.
Protect the pan drippings. If the vegetables start to darken too quickly or the liquid evaporates, add ¼–½ cup broth. Burnt drippings mean bitter gravy.
Rest it. Let the lamb rest 15–20 minutes before slicing. Cut too soon, and the juices run out onto the board instead of staying in the meat.