Preheat oven to 180°C. Line 2 baking trays with baking paper and set aside.

Using a mixer, cream the butter and brown sugar together. Add the vanilla extract and egg and mix well.

In a bowl, combine the flour, oats and 1 cup of the chocolate chips.

Fold in the butter and sugar mixture until well combined.

Roll tablespoon-sized balls of mixture and use the flat bottom of a glass to press them down a little. Sprinkle a few of the remaining chocolate chips on each cookie.

Bake for 20 minutes until pale golden. Leave to cool on the tray for 5 minutes and then transfer to a wire rack to cool.