1. Preheat oven to 160C fan forced.
2. Cream butter and sugars together until light and fluffy. Mix in vanilla and egg.
3. Sift flour and cornflour and add to mix.
4. Refrigerate for 1 hour.
5. Divide dough into 10. Roll into balls, flatten slightly, place on lined baking trays and allow room for cookies to spread.
6. Place 5 buttons in each cookie.
7. Bake in batches in oven for 15 minutes.
8. Remove and cool on wire racks.

Makes 10 giant cookies.