2) Place the beef into the preheated oven and cook for 15 minutes and then turn the heat down to 180C/Gas 4. Cook for about 15 minutes per pound for rare meat, about 1 hour and 15 minutes.
3) Begin cooking the Yorkshire puddings about 20 minutes before the beef is done. Remove the beef from the oven and allow to rest, covered, for about 15 minutes before slicing.
1) In a blender blend the batter ingredients until smooth and then transfer to a bowl. Let the batter stand, covered, for 1 hour.
2) Spoon 1 tsp roast drippings into each cup of three mini muffin pans. Put two mini-muffin pans on a baking sheet and put the remaining pan on another baking sheet.
3) Put the first baking sheet with the two mini muffin pans in the middle of the oven for 3 minutes to heat the drippings in the cups. Working quickly, pour 2 tsp of batter into the hot drippings in each cup and bake in the middle of the oven for 18 minutes, or until the pudding shells are golden and puffed.
4) Remove the shells from the cups with tongs and cool on racks. Repeat the procedure with the other baking sheet. Serve with the beef.
Cook's Note: The shells may be made 3 days ahead and chilled, covered, or 1 month ahead and frozen in airtight containers. Bring the shells to room temperature and re-crisp in a 150C/Gas 2 oven for 10 minutes.