Preheat the oven to 160 degrees C and grease a loaf tin.
Cream the butter and sugar with a wooden spoon until they are nice and fluffy. Add just 1 egg until it is mixed in completely then add the other egg and the sultanas. Mix again until everything is thoroughly mixed. Peel the bananas and, with the back of a fork, mash them well and add them to the mix then stir again.
Sift the flour into the bowl with the rest of the ingredients and fold into the mix, do not over work the mix, just a nice gentle fold will do.
Pour the mix into the loaf tin then place in the oven for about 50 minutes, check the cake after 40 mins by putting a knife or skewer into the middle of the cake; if it comes out clean then it is ready. Remove from the oven and let it cool down in the tin for about 30 minutes. Take out of the tin, and enjoy.
Personally if I can stop anyone eating it, this is much better the next day when it has rested. This will keep for a few days in an airtight tin.