To make the batter, sift the flour into a large bowl, make a well in the middle and add the eggs.
Use a whisk to mix them very well, then gradually pour in the milk, and beat well until the batter is smooth.
Season with salt and pepper to taste.
You can pass the batter through a sieve, if you think it is not quite lump free, as it should be.
Preheat the oven to 220 degrees C. (430 Fahrenheit)
I do not have a Yorkshire puddings tin, which usually has larger holes, but the muffin one does a pretty good job. Of course, the puddings will be smaller.
Add one teaspoon of oil into 6 hole muffin tray and place the tin in the oven for 5 minutes, so that the oil can heat up.
Carefully remove the tin from the oven, and quickly pour the batter evenly between the 6 holes.
Place the tin back in the oven and leave undisturbed for 20 minutes until the puddings have raised and browned.
Remove them from the tin, and top with rolls of roast beef and a good dollop of horseradish sauce.