Preheat the oven to 220° C (430° F).
In a mixing bowl or jug, whisk together eggs, gluten-free flour, and cornflour until smooth and there are no lumps.
Add the milk along with the salt and whisk together until no lumps remain. Your batter should be thin with no lump at all. Use a stick blender if there are some lumps you can't get rid of.
Place the batter in the fridge for 15 minutes, until the oil is piping hot.
When the tin is heated, remove it carefully from the oven and put 1 tablespoon of fat in each hole, and pop it in the hot oven until the fat is piping hot.
Remove the Yorkshire pudding pan from the oven, and quickly fill each hole of the muffin tin with batter about ¾ of the way full then quickly return to the oven.
Bake the Yorkshire puddings for 8 minutes, reduce the heat down to 180° - 360° F and bake them for another 7 to 8 minutes, until they are puffed, golden brown, and crispy. Do not open the oven door at this stage!