1. In a bowl, add the butter and both the sugars together and beat till light and fluffy. 2. Add the milk and vanilla and beat for another minute. 3. Sift in the flour, baking powder and baking soda and mix till you get a soft cookie dough. 4. Add almost all the chocolate chunks, leaving just a little bit aside to add on top later, and mix till the chocolate is evenly distributed. 5. Scoop the dough using an ice cream scoop or spoon. Cover and refrigerate for at least 1 hour. 6. Preheat the oven to 180 degrees C. Line a baking tray with parchment/baking paper. 7. Place the cookie dough on the tray, leaving at least 1-1.5 inches between each ball. Bake the cookies at 180 degrees C for 14-15 minutes. Mid-way through the baking, take out the tray, add more chocolate on top and return the cookies to the oven to bake fully. 8. The cookies will still be soft when done and will continue to become crisp as they cool. 9. Transfer to a cooling rack after 10 minutes, and then to an airtight container. Store for up to a week.