Cut the chocolate into chunks and set aside. You can also use chocolate chips.

In a pan, melt the butter on medium heat. Heat until the butter is lightly brown. Be very careful do not burn the butter. It can be burn within seconds if you are not careful. Set aside for cooling.

In a large bowl, add both castor and brown sugar. Add in the melted butter. Whisk until well combined.

Add milk and vanilla extract, and continue whisking until well combined.

Sift all the dry ingredients. Gently fold in with a spatula. Do not over mix. Fold until the flour is almost disappear. Add the chocolate and fold in until even.

Wrap the bowl with cling film. Refrigerate it for at least 30 minutes. If you desire thicker cookies, then refrigerate overnight. The good thing about this cookie dough is that, you can keep it in fridge for 2 days, and good for use anytime within the 2 days.

Preheat oven at 180°C/355°F.

Use a cookie scoop to scoop the dough into a ball, and place it onto a flat pan with a parchment paper. Place the cookie balls about 2 inches apart as the dough will spread in the oven.

If you like soft chewy and gooey cookies, bake it for about 12 min, just until the edges are lightly brown. If you like crispy cookies, bake for about 18-20 min.

When the cookies are out from the oven, the cookies will be a little soft. Let the cookies cool completely, you will get the texture you desire.