Combine all the dry ingredients (flour, baking soda, salt) in a separate bowl and add it to the butter mixture.

Mix to form cookie dough.

Add the chocolate chips to the cookie dough and mix.

Reserve some cookie dough for topping and form the remaining cookie dough into a square on a piece of baking paper and freeze for 30 minutes. Alternatively, you can add the cookie dough to the brownie batter in a spoonful later.

Grease an 8-inch (20cm) x 8-inch (20cm) square baking tin with oil and line it with an overhang of baking paper on all sides of the pan.

Sift cocoa powder into the chocolate mixture and mix until smooth.

Add light brown sugar, powdered sugar, milk and vanilla mix with a hand whisk until sugar is dissolved.

Add the dry ingredients (flour and salt). Mix until smooth without any lumps of flour. Avoid overmixing. Pour half of the brownie batter into the prepared baking tin, smoothing it into an even layer.

Place the frozen cookie dough square on top of the brownie layer or drop a spoonful of the cookie dough over the brownie layer if you opted not to freeze it.

Pour the remaining brownie batter over the cookie layer, spreading it evenly with a spatula.

Bake in the preheated oven at 340°F (171°C) for 40 minutes or until the brookie is evenly risen and the center is set. Insert a toothpick to check if it's baked. It should have a few moist brownies crumbs but not wet batter.

Immediately after baking, sprinkle extra chocolate chips/chunks on top and gently press the edges with your fingers if they have risen.

Let the brookie cool completely in the tin before lifting it out using the parchment paper overhang.

To portion the brookies neatly, chill them in the fridge or at room temperature overnight. When you’re ready to cut, dip your chef’s knife in hot water and wipe it clean between each cut. First, mark your desired portion sizes on top, then press down to slice through cleanly. This method keeps edges smooth and precise!