Cooking oil spray, to grease
1 cup firmly packed, coarsely grated raw sweet potato (about 110g)
1 cup mashed ripe banana (about 3 bananas), plus extra 1
125ml butter, melted, plus extra 10g butter, melted
3 free-range eggs
1 cup brown sugar, firmly packed, plus extra 1 tsp
1½ cups plain flour
3 tsp baking powder
1 tsp ground cinnamon, plus extra 1/8 tsp
¾ cup icing sugar mixture
2 Tbsp passionfruit pulp
Preheat oven to 180°C fanforced (200°C conventional). Grease a 20 x 10cm loaf tin with cooking oil. Line base and sides with baking paper.
Put sweet potato, mashed banana, butter, eggs and brown sugar in a large bowl. Stir until combined.
Sift in flour, baking powder and cinnamon and mix again until just combined (don’t over beat). Pour batter into prepared tin.
Slice extra banana into long pieces on the diagonal and arrange on top of batter in a single layer. Sprinkle over extra brown sugar and extra cinnamon. Bake for 1 hour 10 minutes or until golden brown and cooked when tested with a skewer. Set aside in tin for 15 minutes to cool then turn out onto a wire rack to cool completely.
Meanwhile, put icing sugar mixture, passionfruit pulp and extra melted butter in a large bowl and mix until combined and smooth.
Drizzle icing generously over cooled cake and serve.