Brown the butter

• Melt three quarters of a cup of butter in a pan on the stove over low heat — any higher and you risk cooking off too much water and burning the butter.
• Stir every 15 seconds or so until you see small brown flecks at the bottom of the pan.
• As soon as they're light golden brown, take the pan off the heat and let it rest until warm but not hot to the touch.

Measure the brown sugar

• Pack the brown sugar against the side of the bag before measuring.
• Level it off with the back of a butter knife for the most accurate measurement.

Mix the wet ingredients

• Pour the warm brown butter into a mixing bowl along with the packed brown sugar, the granulated sugar and a full tablespoon of vanilla extract.
• Mix until just combined.
• Add in a large egg along with an extra egg yolk to enhance the richness of the dough.

Add the dry ingredients

• Weigh the flour, or use the fluff and scoop method: fluff the flour with a large spoon, scoop it into the measuring cup and level it off with a butter knife.
• Add the flour to the bowl along with a little baking soda and salt.
• Fold everything together by hand with a spatula until just combined — mixing any more will make the dough tougher and tighter.

Fold in the chocolate

• Add the chocolate discs (or mini chips or chopped chocolate bars) and fold them through the dough.

Roll the dough

• Use a cookie scoop to portion the dough, then roll it into balls in your hands to smooth the edges.
• Move some of the chocolate pieces to the top of each cookie so you see them when they bake.

Chill the dough

• Cover the dough and let it chill in the fridge for at least one hour, or up to overnight — resting is instrumental to developing maximum flavour and texture.

Bake the cookies

• Let the dough balls come to room temperature.
• Bake on a light coloured cookie sheet at 350°F (175°C).
• To tell if they're perfectly cooked, touch the middle: it should be a little bit spongy while the outside should be hard.

Cool and serve

• Let the cookies cool completely on the pan — they'll continue to cook as they cool and set into the perfect gooey texture.