Place the Brazil nuts onto an oven tray and bake at 160°C FF for 10-12 minutes, or until lightly roasted. Allow to cool.
Cream the butter and sugar until light and fluffy then spread evenly over the base of a fully greased and paper-lined 20cm round baking tin, then sprinkle over the cooled nuts.
Sift the dry ingredients into a mixing bowl then stir through the sugar. In a jug whisk together the oil, eggs and bananas until combined then stir through the dry ingredients until combined. Spoon the mixture into the tin over the prepared base.
Bake at 160 °C FF for 45-50 minutes or until cooked when tested. Turn out onto a cake rack immediately, remove the paper and allow to cool. Serve the cake sliced with a dollop of cream.
Notes
NB: The cake may be served warm or room temp. Reheat desired number of slices in the microwave if so.