This is a place-holder for a more complete version. I've had a lot of trouble finding the right roasting time. Since I use a meat thermometer, that's not the end of the world, but it makes it difficult to time things. See the discussion in my diary for more information. In addition, my original suggestion of 54° seems a little on the high side, so I'm currently aiming for 53°.

Preparation

Set the fan oven temperature to 180°. Cook for about 50 minutes per kilogram until the meat temperature reaches 53°. Leave to stand for 15 minutes, using the juices that collect for a Yorkshire pudding.

Data points

To help me derive a better formula for the cooking time, here are some results of past attempts:

				Final
Date		Weight		temperature		time
1 October 2011		1.27 kg		54°		66 minutes
24 March 2012		1.3 kg		52°		60 minutes