Yorkshire Pudding how............

That's not necessarily a fail, so you know. You can manipulate the center of your puds by controlling the temperature of the batter. Cool or cold batter gets you a denser cup shape which can hold more gravy, and it's more pudding like in texture. On the other hand, warm/room temp batter will more likely give you the sort of hollow you are looking for. It can also be a dense pud if you add in too much flour, or don't let the batter rest before you bake it. Everyone will go on and about how your pan and fat have to be screaming hot when the batter hits it- but that's not necessary. Your oven needs to be, and you can heat the empty tin for a few moments to get that hot- but you do not need to add the oil at that time. Add the oil to an empty hot tin, then add in the batter, and bake it off. It's the heat of the oven that does the trick, if the eggs are beaten well and the batter isn't too dense with flour. They will puff up and then deflate to some degree when out of the oven, too. It's basically the same thing as a popover, except traditionally Yorkshire puds were done in beef fat instead of oil. So if you have a favorite pop over recipe, use that. And if you look for a recipe, try to find one that uses weights instead of scoops and cups. Less likely to fudge up the flour measure that way.