Brown the butter

• Melt the butter in a saucepan over medium heat.
• Keep cooking until the milk solids turn golden brown and smell nutty, about 8 minutes.
• Never melt the butter in the microwave.

Mix the sugars and eggs

• Pour the browned butter into a mixing bowl with the brown sugar and granulated sugar and whisk.
• Add the egg, egg yolk and vanilla extract and whisk until smooth and glossy.

Add the dry ingredients

• Whisk together the flour, cornstarch, baking soda and salt.
• Fold the dry mixture into the wet mixture until just combined.

Fold in the chocolate

• Fold the chopped dark chocolate chunks into the dough.

Chill the dough

• Shape the dough into large balls and chill so the cookies stay thick.

Bake the cookies

• Place the dough balls on a baking tray, spaced apart.
• Bake at 180 °C until the edges are set and the centers are still soft.

Cool and serve

• Let the cookies cool on the tray for a few minutes.
• Serve warm, ideally with ice cream.