Coarsely grate the courgette and tip into the middle of a clean tea towel. Wring out the excess water and put the dry courgette into a bowl. Set aside.

Combine the oats, flour, baking powder and salt in a large bowl. Set aside.

Tip both sugars into a large bowl. Finely chop the mint leaves and rub into the sugars for a couple of mins to release the oil. Add the butter and beat together until light and fluffy. Whisk in the egg.

Add the dry ingredients to the bowl and break in the chocolate. Tip in the courgette and bring everything together to form a dough. Cover and chill for 2 hours.

Heat the oven to 175°C. Line a baking tray with parchment paper. Take 2 tbsp of cookie dough and roll it into a ball. Put on the lined sheet, leaving plenty of space for spreading. Repeat with the remaining cookie dough.

Bake for 15 mins until cooked through and golden brown.