Using a muffin baking tray or a Yorkshire pudding baking tray, divide up the oil between the holes.
In a medium sized bowl, thoroughly mix together the plain gluten-free flour with the cornflour and the salt.
Add both eggs and the milk to the bowl with the flour mixture, and then beat together the ingredients until a smooth, lump-free batter has formed.
Transfer the batter to a pouring jug and allow the batter to rest for 15 minutes.
Place the baking tray into the hot oven for 8 minutes, until the oil is very hot.
Carefully remove the baking tray from the oven, stir the batter, and then divide it up between the holes in the baking tray and return it to the oven.
Allow the Yorkshire puddings to cook for 5 minutes, then turn the temperature down to 400 F for another 20 minutes, until they are risen and golden in color.
Remove the Yorkshire puddings from the oven and serve immediately. Alternatively, they can be cooled and frozen, ready to be taken out and warmed up again in the oven when ready for eating.