Cook the beef mince in a pan on medium heat until just browned and season to taste. Transfer to bowl and leave to cool. Once cool, add the gherkins, onion, cheese, ketchup and mustard and season to taste.
Make spring rolls by filling each spring roll wrapper with about a tablespoon of the mixture and roll up using beaten egg wash to seal.
Heat deep frying oil to 180 degrees. Fry spring rolls a few at a time for approximately three minutes or until golden brown.
Drain on absorbent paper and serve immediately.