Wash and dry the potato
Put the potato in a microwave and cook on 800w for 3-4 minutes. For a lower wattage adjust the time so that you have a potato that is just soft when pressed firmly. If you are cooking more than one potato it will take longer in the microwave. Around 6 minutes for two potatoes and around 8 minutes for four.
Once the potato has been softened, put it into the air fryer. My setting is for a Russell Hobbs Actifry and is airfry at 215C. If you are using a fan oven I suggest a setting of 180C or 200C for a normal oven.
Meanwhile make up the cheese mix by first grating the cheese
Season with salt and pepper and mustard
Stir through the egg and mix well with a fork
Add enough milk to make a thick mixture
After 15 minutes remove the potato from the air fryer.
Cut it in half and scoop out the flesh
Mash the flesh well with a fork then add a teaspoon of the cheese mixture
heap the mix back into the potato skins and press down firmly
Top with enough cheese mixture to cover the potato
Put back into the air fryer for a further 5 to 8 minutes, till the topping is golden and bubbling
Serve immediately