The butter will melt, foam, then turn golden brown with nutty aroma and small brown bits (about 5-7 minutes).

Remove from heat and add cocoa powder and milk or dark chocolate bar in hot butter.Mix thoroughly till there're no lumps in it and set it aside to cool.

•In a bowl add eggs, white sugar, light brown sugar, whisk together until most or all of the sugar granules have dissolved.

•Once the sugar has dissolved, add the brown butter, cocoa powder, melted dark or milk chocolate mixture and vanilla extract. Mix everything together.

•Add the all-purpose flour and salt and mix just until combined, avoid overmixing.

•In a large mixing bowl, add the cold cubed butter and whisk until slightly creamy. Add the white sugar and light brown sugar, then whisk together until well combined and fluffy.

•Add the eggs, vanilla extract, and chocolate chips or chunks. Whisk until fully incorporated.

•Add the flour, baking powder, baking soda, and salt. Gently mix until just combined, do not overmix.

•Preheat the (fan) oven at 166C if you're using dark colour aluminum pan or at 176C if using lighter colour aluminum pan.

•Line a square 8 inch baking tin with parchment paper, leaving overhang for easy removal. Lightly grease the paper.

• First brownie layer. Pour about ½ to ⅔ of the brownie batter into the pan. Spread evenly to form the base.

•Drop large chunks of cookie dough randomly over the brownie batter. Keep them uneven this gives pockets of gooey cookie after baking.

•Final brownie layer. Gently spoon the remaining brownie batter over the fillings.

Finish with More large chunks of cookie dough.

•Bake for 1 hour or it depends on pan size and depth how to check doneness

•Edges: set and slightly pulled from the pan

•Center: soft and slightly tender when hot