80g white sugar
2tsp corn flour
juice and zest of 1 large lemon or 2 small.
Put the whole lot in a saucepan over a low to moderate heat and beat the hell out of it until it turns into lemon curd. Do not stop beating or you will get bits of cooked white egg. Takes approx 3 minutes. Pour into a sterilised jar and leave to cool. Store in the fridge.