Preheat oven to 170°C. Cream the butter and sugars for at least 5 minutes until the mixture becomes light and fluffy.
Add the egg and vanilla extract and beat well.
Add choc chips, flour, baking soda and baking powder. Beat on low speed until just combined (don't overwork the mixture or it can become tough).
Dollop tablespoon sized balls of cookie dough onto lined baking trays. I usually put 5 cookies on each of my 4 trays as these babies spread.
Bake until cookies are golden around the edges, around 12-14 minutes.