Preheat oven to 180 degrees. Grease and flour a loaf pan.
Beat the butter and sugar till fluffy. Beat in the tahini paste.
Add eggs one at a time and beat at each addition. Add the vanilla extract.
Sift in the whole wheat flour, corn flour, baking soda and salt into the beaten butter mixture.
Add the milk and mashed banana and fold the mixture using a spatula gently till well combined and moist. Do not overmix.
Pour into the prepared loaf pan and bake for 45 minutes or till a skewer comes out clean.
Cool in pan for 10 minutes, flip onto a rack and cool completely. Slice and serve with a cup of black coffee!