Simple Double Chocolate chip cookie

I did a mid night bake after coming back home from work. Friday princess going for school excursion and she requested for chocolate chip cookie. I need to spend some time to look for a simple and new recipe to test at the same time. Now presenting you ....
Ingredients
115g butter
180g self rasing flour (sifted)
1 1/2 tbsp cocoa powder
70g castor sugar * will cut down another 10g in next bake
40g light brown sugar
1 egg (lightly beaten)
a pinch of salt
1/4tsp vanilla essence
1/2 cup mini semi sweet chocolate chips

Method

1. Cream butter and sugar till creamy
2. Add egg and blend well
3. Pour in flour, cocoa powder, vanilla essence, salt & chocolate chip and mix well
4. Chill the dough for about 15-30 mins to set
5. Scoop the dough with a spoon and drop it on the lined tray
6. Bake at 175c for 15-20 mins