Meanwhile, make the yorkshire pudding batter up by sifting the flour with a pinch of salt.
Make a well in the centre of the flour and add the egg. Use a metal fork to gradually pull in all the flour. Add the milk bit by bit till you have a smooth batter. Add cold water till the consistency of the batter is similar to single cream.
When the beef is resting, preheat a pre-greased Yorkshire pudding pan (either a muffin tin or a small roasting tray). Once the fat is smoking, add the batter - about a tablespoon per muffin pan, or so that you have a layer about half a cm on the base of the roasting pan
Allow to cook for 20 minutes, till puffed up and golden. Under no circumstance open the oven door till the puddings are cooked.
Slice the beef thinly. Serve with the Yorkshires, roast potatoes, homemade gravy and whatever seasonal vegetables you choose