I have made this a few times, keeps about 3-4 months in the refrigerator, goes well as a filling in cakes, or on scones, muffins,fesh bread or whatever takes your fancy!!!
Mash the banana, using a wooden spoon oR fork. Melt the butter slowly in a heavy based pan, then add the sugar, bananas, lemon rind and juice. Cook for 10 minutes.
Beat the eggs with a wooden spoon, then gradually beat in 3 tablespoons of the banana mixture, (doing this; perevents the eggs from curdling.).
Pour onto the remaining banana mixture, stirring constantly, until the mixture thickens and is thick enough to coat the back of a spoon; but do not boil.