How Long to Cook Rack of Lamb at 400°F: Perfect Timing Guide

For a perfect medium-rare rack of lamb roasted at 400°F, cook for 15-18 minutes (approximately 5 minutes per pound). The internal temperature should reach 130-135°F for medium-rare, measured with a meat thermometer inserted into the thickest part of the meat away from the bone.

Nothing elevates a special dinner like a perfectly cooked rack of lamb—crisp on the outside, tender and rosy within. But hitting that sweet spot requires precise timing and temperature control. Get it wrong, and you'll end up with overcooked, dry meat or undercooked disappointment. This guide delivers exactly what you need: science-backed timing, professional chef techniques, and troubleshooting tips to ensure success every time.

Why 400°F Is the Ideal Temperature for Rack of Lamb

Cooking at 400°F creates the perfect balance between developing a beautiful sear and maintaining tenderness. Lower temperatures risk overcooking the exterior before the interior reaches proper doneness, while higher temperatures can cause uneven cooking. This temperature allows for efficient heat transfer while minimizing the risk of drying out the delicate meat.

Preparation: Setting Up for Success

Proper preparation significantly impacts your final result:

• Bring to room temperature: Remove lamb from refrigerator 45-60 minutes before cooking
• Pat dry thoroughly: Moisture is the enemy of proper searing
• Season generously: Salt at least 45 minutes before cooking to allow penetration
• Prepare your roasting pan: Use a rack to elevate the lamb for even air circulation

Exact Cooking Times at 400°F: The Complete Guide

While 15-18 minutes is the standard for medium-rare, several factors affect precise timing. The following table provides detailed guidance based on USDA food safety standards and professional chef recommendations:

Lamb Weight	Cooking Time at 400°F	Internal Temperature	Doneness Level
1.5 lbs (6-8 ribs)	12-15 minutes	120-125°F	Rare
1.5 lbs (6-8 ribs)	15-18 minutes	130-135°F	Medium-rare (recommended)
1.5 lbs (6-8 ribs)	18-22 minutes	140-145°F	Medium
2 lbs (8 ribs)	18-22 minutes	130-135°F	Medium-rare
2.5 lbs (8-10 ribs)	22-26 minutes	130-135°F	Medium-rare

Critical Factors That Affect Cooking Time

Understanding these variables helps you adjust timing for perfect results:

• Bone-in vs. boneless: Bone-in racks require slightly longer cooking (about 2-3 minutes more) as bone conducts heat differently
• Starting temperature: Lamb straight from the refrigerator needs 3-5 minutes longer than room-temperature meat
• Oven accuracy: Use an oven thermometer to verify actual temperature (many ovens vary by 25°F+)
• Rack position: Middle rack position ensures most even cooking

The Science of Carryover Cooking: Why Resting Matters

Professional chefs understand that cooking doesn't stop when the lamb leaves the oven. During the essential 10-15 minute resting period, internal temperature continues to rise 5-10°F due to residual heat—a phenomenon known as carryover cooking. This is why you should remove the lamb from the oven when it's 5°F below your target temperature.

According to food science research from the University of California's Department of Food Science and Technology, this resting period allows proteins to relax and juices to redistribute throughout the meat. Skipping this step causes valuable juices to escape when carving, resulting in drier meat. Their studies confirm that proper resting improves moisture retention by up to 30%.

Pro Tips for Perfect Results Every Time

• Use an instant-read thermometer: Visual cues can be misleading; a thermometer provides certainty
• Rotate the pan halfway: Ensures even cooking in ovens with hot spots
• Monitor temperature rise: Check every 2-3 minutes during the final cooking stage
• Consider the fat cap: Score and render fat side down for 2-3 minutes before roasting for extra crispness
• Let carryover work for you: Remove at 125°F for medium-rare (will reach 130-135°F after resting)

Troubleshooting Common Cooking Issues

Problem: Uneven cooking
Solution: Rotate the rack 180 degrees halfway through cooking and ensure proper air circulation around the meat

Problem: Overcooked exterior, undercooked interior
Solution: Start at higher temperature (425°F) for 5 minutes, then reduce to 400°F for remainder of cooking time

Problem: Meat drying out
Solution: Baste with herb-infused oil during cooking and never skip the resting period

How to Test Doneness Without a Thermometer

While a thermometer is ideal, you can use the finger test method:

• Rare: Feels like the fleshy part of your palm below the thumb when your hand is relaxed
• Medium-rare: Similar to the same spot when you touch thumb to index finger
• Medium: Resembles the feel when thumb touches middle finger

However, this method requires practice and is less reliable than a thermometer, especially for beginners.

Serving Suggestions for Your Perfectly Cooked Rack of Lamb

After resting, carve between the bones into individual chops. Pair with:

• Fresh mint sauce or chimichurri for classic flavor
• Roasted root vegetables like carrots and parsnips
• Red wine reduction sauce for special occasions
• Crispy roasted potatoes for a hearty meal

How long to cook a 2-pound rack of lamb at 400 degrees?

For a 2-pound rack of lamb at 400°F, roast for 18-22 minutes to reach medium-rare (130-135°F internal temperature). Always use a meat thermometer for accuracy, as oven temperatures and starting meat temperatures can affect cooking time.

Should I cover rack of lamb when roasting at 400°F?

No, never cover rack of lamb when roasting. Covering traps steam which prevents proper browning and crust formation. For the best results, roast uncovered on a rack in a roasting pan to allow air circulation around all sides of the meat.

What temperature should rack of lamb be cooked to for medium-rare?

For medium-rare rack of lamb, the internal temperature should reach 130-135°F when measured with a meat thermometer in the thickest part of the meat away from the bone. Remember to remove the lamb from the oven at 125°F as the temperature will continue to rise 5-10°F during the resting period.

How long should rack of lamb rest after cooking?

Rack of lamb should rest for 10-15 minutes after cooking. This resting period allows the proteins to relax and the juices to redistribute throughout the meat. Cutting too soon causes valuable juices to escape, resulting in drier meat. Tent loosely with foil during resting to maintain temperature.