Step 1

Preheat oven to 180°C/160°C fan forced. Grease the base and sides of a 20cm square cake pan with oil then line base and sides with baking paper.

Step 2

Use electric beaters to beat the butter and caster sugar in a bowl until pale and creamy. Beat in the eggs until combined. Beat in the banana and mixed spice until well combined. Transfer mixture to a large bowl. Use a large metal spoon to fold in the flour then the milk until combined. Spoon cake mixture into prepared pan.

Step 3

To make the topping, combine the flours, brown sugar and cinnamon in a bowl. Use fingertips to rub the butter into the flour mixture until mixture resembles coarse crumbs. Stir in the pecans. Evenly sprinkle crumble mixture over cake mixture. Bake for 1 hour 10 minutes or until a skewer inserted in the centre of cake comes out clean. Set aside in the pan to cool completely.