Preheat the oven at 375*F / 190*C.
Line a 7 inches square baking pan with butter or parchment paper. You may use a 6 inches oven safe Pyrex dish also. The baking time may vary a little bit with pyrex.
Take a medium size mixing bowl. Sift all purpose flour, coco powder, baking soda and salt in it. MIx with a fork and set aside.
Take a large mixing bowl. Add butter, brown sugar and granulated sugar to it.
Take the electric beater and beat this mixture for about 2 minutes till butter and sugars are mixed and it becomes soft and slightly fluffy.
Add vanilla extract + flour mix + milk to the butter mix. Mix with a fork till all the flour is mixed well in the butter. Your brownie batter is ready. It is tighter than the cake batter.
Now add 1 cup chocolate chips to the batter. Save 2 tbsp for later.
Transfer this batter to the lined baking pan. Spread it out evenly with either a spreading spatula or with your finger tips of the hand.
Sprinkle the remaining 2 tbsp of chocolate chips on top. Press these down a little bit.
Bake the brownie for 25-30 minutes. Start checking at 23 minutes for done-ness, with the wooden party pick inserted in the middle to check if it is fully baked.
Once the toothpick comes out clean, switch off the oven. Take the brownie out.
Let it sit in the pan for 5 minutes.
Carefully take it out with parchment paper and let it cool down.
Once cooled, cut in desired shape and size. Eat fresh or store for later.