To make the batter, lightly beat the eggs in a large jug, then beat in the pectin, tapioca starch, flours and 4 to 5 pinches of sea salt, using a balloon whisk, to make a smooth paste.
Add half the milk and whisk again until smooth. Whisk in the rest of the milk to make a smooth batter. Cover and set aside for 1 to 6 hours, or up to 24 hours in the fridge.
If you are having these with a roast dinner, get everything ready so that the puddings can bake in the oven while you rest your meat for 20 minutes.
Divide the fat amongst 10 holes of a muffin tray, or for one large pudding, put it into a 20cm x 30cm roasting tray. Place the tray in the oven to heat up (along with the meat for the last 10 minutes of its roasting time).
When you take the meat out, turn the oven as high as it will go (ideally 250°C/fan 500ºF/gas 10). When it reaches this temperature, take the tray out of the oven and place over a medium heat on the hob, trying to get an even spread of heat under the tin.
Wait until the fat is starting to smoke. Meanwhile, give your batter a good whisk. Quickly and carefully pour the batter into the tray, dividing it evenly between the 10 moulds if making individual puddings – the batter will bubble in the hot fat as you add it.
Put the tray straight into the oven and turn the heat down to 240°C/475ºF/gas 9.
Bake for 10 minutes, during which time the puddings should puff up into all manner of exciting and improbable shapes. Turn the oven down to 200°C/400ºF/gas 6 and bake for a further 10 minutes until the puddings are deep golden brown and crisp on top.
Don’t open the oven to check them at any point or they will collapse – just hold your nerve and get on with the gravy. Eat the Yorkshire puddings right away, with your roast.