Prepare the Yorkshire pudding batter after the beef has roasted for 1 hour, then, while the roast rests, add beef fat to the batter and get the puddings into the oven. While the puddings bake, complete the jus. An accurate oven temperature is key for properly risen puddings, so check your oven with an oven thermometer before making this recipe. Work quickly to fill the muffin tin with batter, and do not open the oven door during baking.