Beat butter or margarine with an electric mixer on medium to high speed for 30 seconds. Add one cup (125g) of the flour, the sugar, eggs, baking powder, vanilla, cinnamon, bicarb soda and cloves. Beat until thoroughly combined.
Stir in the remaining flour. Beat in bananas and walnuts. Drop by rounded teaspoons 5cm apart onto a greased baking tray. Bake for 8 to 10 minutes or until edges are lightly browned. Cool biscuits on a rack.