This post contains affiliate links. Please see our disclosure policy.
This garlic butter rack of lamb with baby potatoes is so easy to make and absolutely delicious! The lamb is seared, coated in a flavorful garlic rosemary butter, and finished in the oven until perfectly medium-rare.
The crispy roasted baby potatoes make this a complete dinner that looks fancy but is actually super simple to make! Love lamb chops? Check out these honey garlic lamb chops!
Table of Contents
If you’ve never cooked rack of lamb before, don’t let it intimidate you! It’s actually incredibly simple, and the results are restaurant-quality. I love that the lamb and potatoes cook at the same temperature, so everything comes together without much fuss.
The garlic butter is made with fresh garlic, rosemary, and a little Dijon mustard. It melts right into the hot lamb, adding so much flavor. And the potatoes? They’re crispy on the outside, tender on the inside, and seasoned generously with garlic and Italian seasoning.
Ingredient Notes
See the recipe card below for ingredient quantities and complete instructions.
- Rack of lamb: I used a 2-pound rack of lamb. If yours is smaller or larger, you’ll need to adjust the cooking time.
- Vegetable oil: Perfect for searing the lamb over high heat.
- Salted butter: Make sure it’s softened so it’s easy to mix with the other ingredients.
- Dijon mustard: Just one teaspoon adds a subtle tanginess without overpowering the lamb.
- Baby potatoes: Slice them in half so they roast evenly and develop a crispy, golden surface.
Top Tips
- Pat the lamb completely dry. Moisture prevents proper browning, so don’t skip this step.
- Get the skillet nice and hot. You want a beautiful golden crust on the lamb before it goes into the oven.
- Sear all sides. Don’t just sear the front and back! Briefly searing the edges gives the lamb even better flavor.
- Don’t worry about the butter melting. The skillet and lamb will be extremely hot, so the garlic butter will melt almost immediately. That’s perfectly fine!
- Don’t overcook the lamb. A meat thermometer is your best friend when cooking rack of lamb.
- Roast the potatoes cut-side down. This helps create a delicious golden crust.
- Let the lamb rest before slicing. Cutting it immediately can cause the juices to run out.
FAQs
How do I know when my rack of lamb is medium-rare?
For medium-rare lamb, aim for a final internal temperature of approximately 130–135°F after resting. Since the temperature continues to rise after removing the lamb from the oven, you can generally pull it around 125–130°F, depending on how much carryover cooking you expect. Insert a meat thermometer into the thickest part of the meat without touching the bone.
Why do you sear the lamb before roasting it?
Searing develops a flavorful, browned crust that you wouldn’t get from roasting alone. It also gives the lamb a beautiful appearance.
Can I cook the lamb longer?
Absolutely! If you prefer medium or medium-well lamb, continue roasting until it reaches your desired internal temperature. Use a thermometer because cooking times vary depending on the size and thickness of the rack.
Storage and Reheating
Storage: Allow leftovers to cool, then refrigerate the lamb and potatoes in separate airtight containers for up to 3–4 days.
Reheating: For the lamb, gently reheat in a covered skillet over low heat with a little butter until warmed through. Keep in mind that reheating medium-rare lamb may cook it further.
For the potatoes, reheat in a 400°F oven or air fryer until hot and crispy.
Tried this recipe? Please leave a star ⭐️⭐️⭐️⭐️⭐️ rating in the recipe card below and/or a review in the comments section further down the page. Also, please consider following me on Facebook or Pinterest!
Garlic Butter Rack of Lamb with Baby Potatoes
Equipment
- Large cast iron skillet or any heavy bottom skillet
- Large baking sheet
- Meat Thermometer
- tongs
- Small mixing bowl
- Pastry Brush
Ingredients
For the Rack of Lamb
- 1 rack of lamb, about 2 pounds
- 2-3 tablespoons vegetable oil
- 4 tablespoons salted butter, softened
- 4 garlic cloves, finely minced
- 1 sprig fresh rosemary, finely minced
- 1 teaspoon Dijon mustard
- Kosher salt and freshly ground black pepper, to taste
For the Baby Potatoes
- 1 1/2 pounds baby potatoes, halved
- 2-3 tablespoons olive oil
- 2 teaspoons granulated garlic
- 1 teaspoon Italian seasoning
- 3 tablespoons Parmesan cheese, freshly grated
- Kosher salt and freshly ground black pepper, to taste
Instructions
- Preheat your oven to 400°F.
- Slice the baby potatoes in half and place them on a baking sheet. Drizzle with olive oil and season generously with kosher salt, black pepper, granulated garlic, and Italian seasoning. Toss well and arrange cut-side down in a single layer. Roast for 25 minutes while you prepare the lamb.
- In a small bowl, combine the softened salted butter, minced garlic, minced rosemary, and Dijon mustard. Mix well and set aside.
- Pat the rack of lamb completely dry with paper towels and season generously with kosher salt and black pepper on all sides.
- Heat the vegetable oil in a large cast iron skillet over medium-high heat. Once hot, place the rack of lamb fat-side down and sear for 4 minutes. Flip and cook for another 2 minutes. Using tongs, carefully sear all remaining sides and edges for a few seconds each until nicely browned.
- Remove the skillet from the heat and brush the garlic rosemary butter mixture all over the lamb. The butter will melt immediately when it touches the hot meat, and that’s completely fine! Spread the garlic and rosemary evenly over the lamb.
- Transfer the cast iron skillet to the 400°F oven and roast for approximately 10 minutes for medium-rare, or until the lamb reaches your preferred temperature. For medium-rare, aim for a final temperature of 130–135°F after resting.
- Remove the lamb from the oven, transfer it to a cutting board, and let it rest for 6–7 minutes before slicing between the bones.
- Continue roasting the potatoes until they’ve cooked for approximately 35 minutes total, or until golden brown, crispy, and fork-tender. Sprinkle with freshly grated Parmesan cheese if desired.
- Slice the lamb into individual chops and serve immediately with the roasted baby potatoes. Enjoy!
Notes
- Rare: 125°F
- Medium-Rare: 130–135°F
- Medium: 140–145°F
- Medium-Well: 150–155°F
- Well-Done: 160°F and above
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
