Grease and line a 2lb loaf tin (approximately 10 x 20 cm) or use a silicone loaf tin liner.
Heat the oven to 180°C/gas mark 4.
Use a fork to mash the bananas in a mixing bowl.
Add the sugar and stir to combine.
Add the flour (sifted), eggs, oil and milk and stir for 30 seconds.
Add the walnuts and mix in gently.
Pour the mixture into the prepared cake tin.
Bake for 50-55 minutes, until a skewer inserted into the middle of the cake comes out clean.
Leave in the tin for 5 minutes.
Turn the cake out on to a wire rack and leave to cool.