Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done.
Method. 1  Preheat the oven to 220ºC. 2  Brush the roast lightly with oil and season with salt and pepper. 3  Place the lamb on a rack in a roasting dish. 4  Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done. 5  For ease and accuracy use a meat thermometer. 1 Place the lamb on a rack in a roasting dish. 2  Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done. 3  For ease and accuracy use a meat thermometer. 1 Preheat the oven to 220ºC. 2  Brush the roast lightly with oil and season with salt and pepper. 3  Place the lamb on a rack in a roasting dish. 4  Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done. 5  For ease and accuracy use a meat thermometer. 1 Place the lamb on a rack in a roasting dish. 2  Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done. 3  For ease and accuracy use a meat thermometer. Directions. 1  Prepare the racks of lamb at least 1 hour (or up to 4 hours) before cooking: Chop together the garlic, salt, rosemary, and pepper to make a coarse rub. 2  Preheat oven to 425° F. Heat a roasting pan in the oven for 10 minutes. 1 Pat the racks of lamb dry with paper towels and coat lightly with the olive oil. 2  Place the racks flesh-side down in the pan. 3  Roast 15 to 20 minutes or until an instant-read thermometer inserted in the thickest part reads 145° F for medium rare (the temperature will rise about 10° when the lamb is out of the oven). 1 As a rough guideline, for 500g of lamb cook for 10-15 minutes for rare; 15-20 minutes for medium; and 20-25 for well done. 2  If you're using a meat thermometer, the internal temperature should be at least 55-60ºC for rare to medium-rare. 1 Select your roast from a quality butcher, looking for lamb that is pink, bright and healthy. 2  If you have time, bring your lamb to room temperature before you roast it, as this will help it cook more evenly. 3  Even 10-15 minutes out of the fridge beforehand will help. 1 Place the racks flesh-side down in the pan. 2  Roast 15 to 20 minutes or until an instant-read thermometer inserted in the thickest part reads 145° F for medium rare (the temperature will rise about 10° when the lamb is out of the oven). 3  Transfer the racks to a carving board. 4  Let rest for 10 minutes. 1 Pat the racks of lamb dry with paper towels and coat lightly with the olive oil. 2  Place the racks flesh-side down in the pan. 3 Place in the bottom of a large roasting pan. Place the lamb on top of the potatoes and roast for 1 1/4 to 1 1/2 hours, or until the internal temperature of the lamb is 135 degrees (rare) or 145 degrees (medium). Remove from the oven and put the lamb on a platter; cover tightly with aluminum foil As a guideline, roast for 20 minutes per 500g. and a further 20 minutes after that. For a mini roast at 350-400g, 35-40 minutes will cook the meat to medium doneness. We recommend checking the internal temperature of the meat with a meat thermometer. The meat will need to be 140°F degrees for rare, 160°F for medium and 170°F for well done.  As always, there are many different recipes for cooking a leg of lamb. Elise cooks her leg of lamb with the bone in by starting at 425 degrees for 20 minutes then turns the oven down to 300°F and continues to roast the meat for about 10-12 minutes per pound for medium rare lamb. For beginner cooks, the smaller boneless roast is easier to carve. Besides, it just fit into my 15-inch long roasting pan, and my larger roasting pan is not as photogenic! The steps involved in making this boneless leg of lamb are: 1  Make a “spice-rub” with garlic, thyme, rosemary, oregano and black pepper. Place in the hot oven after 5 minutes then turn down to 180c and cook for about 1 hour or until your required degree of doneness. Remove from the oven and rest the meat for 10 minutes before carving.. Mini Lamb Roast with Garlic & Rosemary by Neal Jackson; Multi Award Winning Chef & Owner of Jackson’s Restaurant, Perth. 
http://www.fromnature.com.au/lamb-mini-roast-with-oregano.htm http://www.fromnature.com.au/lamb-mini-roast-with-oregano.htm http://www.realsimple.com/food-recipes/browse-all-recipes/roast-rack-lamb http://www.taste.com.au/news+features/articles/5821/make+the+perfect+mini+lamb+roast http://www.realsimple.com/food-recipes/browse-all-recipes/roast-rack-lamb http://www.foodnetwork.com/recipes/ina-garten/herb-roasted-lamb-recipe.html http://www.simplybeefandlamb.co.uk/cuts-beef/beef-mini-roast http://startcooking.com/how-to-cook-a-leg-of-lamb http://www.ameliapark.com.au/recipes/Mini_Lamb_Roast.pdf
how long to cook a mini roast lamb