Preheat the oven to 500F or higher.
Place your muffin tin in the oven to pre-heat it.
Pour a little bit of oil in the bottom of each muffin divot, roughly ¼ the depth of the cup and return the pan to the oven.
Pour the batter into the now-hot oil, being careful not to over-flow the muffin tin. Return it to the oven and bake for 8-12 minutes, or until they puff up and brown on top.
Remove the pan from the oven and then pick the Yorkshires out of the pan, cool them on a wire rack.