Heat the butter in the microwave until soft. Add a pinch of salt if the butter is non-salted. Mix the ingredients one by one in the order listed.

Add the non-sifted, all-purpose flour into the bowl, mix until it's no longer floury, then add the chocolate chips. Cool it in the refrigerator for 1 hour.

Rip the batter into small pieces (know that the batter spreads twice as big while baking). Roll out to about 1cm thickness and bake for 7 minutes in a 180℃ preheated oven.

The center rises after 7 minutes, so push it back down with the center of a spoon. Do not move the spoon, be gentle.

Pushing down on the center prevents a raw middle and makes for a yummy texture.

They're also delicious without cocoa. Stick in some marble chocolates for a cute variety. In this version, I pushed the center before baking.

Brown sugar gets hard as a rock after opening, so roll it in a bag and remove air pockets, and keep it in a separate plastic bag for storage.