Step 1

Using an electric mixer, beat butter and sugars until pale and creamy. Add egg. Beat well to combine. Add oats and flours. Stir with a wooden spoon to combine.

Step 2

Preheat oven to 190°C/170°C fan-forced. Line 2 baking trays with baking paper. Add banana and chips to dough. Stir to combine. Refrigerate for 45 minutes to firm slightly.

Step 3

Roll 2 level tablespoons of mixture into 16 balls. Place onto prepared trays, allowing room for spreading. Using the palm of your hand, slightly flatten to form a 5.5cm round. Bake for 12 to 14 minutes, swapping trays after 10 minutes, or until light golden. Stand cookies on trays for 5 minutes. Transfer to a wire rack to cool.

Step 4

Place cookies on a sheet of baking paper. Spoon chocolate into a snap-lock bag. Snip off one corner. Drizzle chocolate over cookies. Stand until chocolate sets. Serve.