In a bowl, mix the egg with salt and pepper. Add it to the squid rings and mix.
In another bowl mix the flour, potato starch, salt and pepper. Remove the squid from the egg and place them in the flour mix. Remove them and repeat with the rest.
Preheat the oil to medium-high heat (180°C/350°F) and fry the squid in batches. Be careful to keep children and liquids away.
Remove the squid from the oil and place it in a bowl with kitchen paper to absorb the excess oil.