Help!!! 12.25 lb bone in prime roast... how long to get to med rare - 2.5 hours at 325? Thank you in advance!
Do you have a thermometer? That's really the best way to check for doneness. 130 degrees fahrenheit for medium rare. That said, if you have the time I would try this technique from Serious Eats: http://www.seriouseats.... 3.5-4 hours at 200 degrees then rested and seared. Good luck!
Indeed if you scroll down you will see that this topic has been thrashed around massively already here. But yes it's the internal temperature that matters. In a home oven you will hopefully end up with more or less medium-well done end pieces and rare in the middle.