Rosemary Garlic Roasted Lamb with Potatoes and Fennel

We’re springing into the season with an easy Easter lamb recipe that brings the meat and potatoes together in one pan. Rosemary Garlic Roasted Lamb with Potatoes and Fennel is served with my mother’s signature mint sauce. This one-pan leg of lamb is packed with flavor.

How do you celebrate—Easter brunch, lunch, or dinner? I grew up enjoying a traditional British late lunch or early dinner, much like this one-pan roast leg of lamb with vegetables and mint sauce. Lamb is the most popular protein to serve for Easter.

Lamb Ingredients:

• Leg of lamb
• Oil (vegetable or olive oil)
• Salt & Pepper
• Garlic cloves
• Rosemary
• Potatoes
• Fennel
• Onion

Mint Sauce Ingredients:

• Sugar
• Hot water
• Cold water
• Malt vinegar
• Mint leaves

Roast Lamb Seasoning

I love to season lamb simply but effectively by inserting garlic and fresh rosemary directly into the meat. This method infuses the lamb with flavor as it roasts, eliminating the need for a marinade. I rub the outside with oil and lightly sprinkle it with salt and pepper—nothing more. 

All the flavors come together beautifully, especially when served with mint sauce.

Choosing the Best Lamb for Roasting

If you have access to a butcher, it’s always best to ask for their recommendation. But if you don’t, here are a few tips to help you choose the best cut yourself:

1. Look for a rosy pink color

• Fresh lamb should be light to medium pink (for younger lamb).
• Darker red means the lamb is older (closer to mutton)—stronger flavor, but tougher.

2. Marbling is magic

• You want fine, even streaks of fat running through the meat—not big globs.
• Marbling = flavor and tenderness.

3. Fat should be white and firm

• Good lamb fat is creamy white, not yellow or waxy.
• Soft or discolored fat? Skip it.

4. Know your cuts

• Loin chops: tender and quick to cook (like mini T-bones).
• Leg of lamb: great for roasting—look for even shape and a nice fat cap.
• Shoulder: flavorful and ideal for slow cooking.
• Rack of lamb: fancy and perfect for dinner parties.

5. Trust your nose

• It should smell fresh—no sour or “off” odors.

6. Check packaging and labels

• Vacuum-sealed is great if you’re not buying from a butcher.
• Look for terms like:
  • “Pasture-raised” or “grass-fed” (more natural diet = richer flavor).
  • “Spring lamb” (more tender and mild).
  • Avoid any that say “previously frozen” if you’re looking for peak texture.

Easter Roast Lamb

For this Rosemary Garlic Roasted Lamb with Potatoes and Fennel, I used a boneless leg of lamb. You can use a bone-in leg of lamb as well—it just takes a bit longer to roast. I always recommend relying on a meat thermometer rather than cooking time, since not all ovens are accurately calibrated. This ensures perfectly cooked meat every time.

Roasting Lamb on a Bed of Vegetables

Using a large roasting pan and placing the lamb on top of the potatoes and fennel serves two purposes: it cooks the vegetables at the same time in the same pan—saving on cleanup—and it infuses them with incredible flavor. No roasting rack needed.

Season the potato slices simply with herbs, salt, and black pepper, then spread them across the bottom of your roasting pan. Top with fennel and onions for a deliciously flavorful combination.

Lamb Roasting Times

Lamb, like beef, can be roasted to your preferred taste and stays juicy and tender when cooked properly. Cooking time will vary depending on whether your lamb is bone-in, so it’s best to use a meat thermometer. Aim for an internal temperature of:

• 125°F / 52°C for medium-rare
• 130°F / 55°C for medium
• 145°F / 62°C for medium-well
• 150°F / 65°C for well-done

Be sure to tent the lamb with foil after roasting and let it rest to retain its juices—just as you would with beef.

Mint Sauce with Lamb

As a rule in my house, you can’t have roast lamb without mint sauce. While most people are familiar with mint jelly, in England, we prefer a simple mint sauce. It’s made easily with freshly chopped mint, malt vinegar (very British), sugar, and water.
This mint sauce is my mother’s recipe, and I would help her make it whenever we had roast lamb. We always had large bushes of mint growing in the garden, and it was my job to pick it.

Easter Side Dishes

So that takes care of the main event (lamb) and potatoes. For the EASIEST and tastiest veggie side dish, I have Roasted Carrots with Green Spring Garlic Pesto that will not only knock your socks off, but the socks off everyone you’re serving. Metaphorically speaking, of course…

Easter Brunch 

If you’re serving Easter brunch, I’ve got a delicious selection of dishes for you—from Ricotta and Spinach Frittata and Baked Breakfast Potatoes with Eggs to something sweet like Orange and Apple French Toast Casserole. And don’t forget the Traditional Hot Cross Buns left over from Good Friday!

Easter Ham

Another traditional Easter dish is ham, and Mandarin Orange Spiced Glazed Ham is perfect if you’re not a fan of lamb—or serve both for the best of both worlds.

Leftover Roast Lamb

Leftovers are just as good, but they must be eaten within 3-4 days. The uses are endless—from making a simple, tasty sandwich to adding it to Curry, Fried Rice, or a Savory Meat Pie.

Here are a few tips for your leftover lamb:

1. Cool it quickly

• Let it rest at room temp for no more than 2 hours.
• If you’re in a rush, slice it and spread it out to cool faster.

2. Airtight is your BFF

• Store in an airtight container or wrap tightly in foil or cling wrap.
• Bonus points if you wrap in foil and put in a sealed container — double protection.

3. Refrigerate like a champ

• Pop it in the fridge and it’ll last 3 to 4 days.
• Keep it near the back (coldest part), not in the fridge door.

4. Reheating

• Reheat gently to avoid drying it out.
• Wrap in foil and warm in a low oven (about 300°F / 150°C) with a splash of broth or water.
• Or pan-fry it quickly for crispy edges.
  

If you’ve made my Rosemary Garlic Roasted Lamb with Potatoes and Fennel, please leave a star rating in the recipe card. You can also ask a question or leave a comment below.