Whenever you are cooking meat, such as a small roast of lamb, you should have on hand an instant-read thermometer. This kind of thermometer makes it easy to know the right doneness of your meat. You insert it into the center, or the thickest part, of your roast. Make sure it is not near any bones, as that will disrupt your meat temperature.
According to the culinary text 'On Cooking - A Textbook of Culinary Fundamental," by Sarah R. Labensky, Alan M. Hause, and Priscilla A. Martel, the following can be used to determine doneness of roasts:
Very Rare - 125 to 130F - 12-15 minutes per pound
Rare - 130 to 140F - 15 - 18 minutes per pound
Medium - 140 to 150 F - 18 to 20 minutes per pound
Well Done - 150 to 165 F - 20 to 25 minutes per pound
Note: The temperatures given are internal temperatures of your meat that allow for carryover cooking. Carryover cooking occurs after food is removed from a heat source. It is accomplished by the residual heat remaining in the food.
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