Prepare 2 large potatoes, peel them and cut off the uneven parts.
Cut the potatoes into 1/2" wide slices and put them in a pot.
Pour off the water and drain them twice. (Note 1)
Boil a pot of hot water and add the sliced potatoes. Boil them for 2 minutes.
Wash them and rinse them with cold water.
Use kitchen paper to wrap the potato slices dry.
Put all the potatoes in a plastic bag and add 2 tablespoons of cornstarch. Mix well and remove excess cornstarch and set aside. (Note 2)
Prepare a saucepan, pour in the butter and add the flour after the butter has melted.
Stir the flour for 1 minute, add milk, 4 slices of cheddar cheese and salt. Stir well and set aside.
Prepare a pan to bring the oil to the boil once it has reached a temperature of 160°C/320°F. (Note 3)
Add the potatoes and fry over a low heat for 3 minutes. Remove them to a plate.
Fry them again over a high heat for 2 to 3 minutes until they are golden brown.
Now you can enjoy them with cheese sauce.