Ingredients
Equipment
Method
- Preheat your oven to 350°f (180°c). Grease and line an 8" (20cm) non-stick baking pan. Leave the parchment extending over the sides to form a sling. You can secure it with binder clips if you like.
- Place the butter in a medium saucepan over medium heat. Cook until melted, then continue cooking, swirling the pan often and stirring with a whisk, until the butter foams, turns golden brown, and becomes nutty. This should take 3-4 minutes.
- Weigh out 110g of the brown butter into a medium bowl. Let it cool for 15-20 minutes so it doesn't scramble the eggs.
- Add the brown sugar and granulated sugar to the bowl with the brown butter and mix to combine.
- Add the egg and whisk well for 1-2 minutes, or use an electric mixer, until the mixture lightens in color and thickens.
- Add the vanilla and mix well.
- Add the flour, baking powder, and salt. Mix with a rubber spatula until some flour streaks remain. This prevents overworking the dough.
- Add the chocolate and mix to incorporate with a rubber spatula.
- Press the dough into the prepared pan, smoothing it down with an offset spatula. You can add a few extra chocolate chunks to the top if you wish.
- Bake for 20 to 22 minutes, until the top is golden brown and set, and the edges have started to firm up. For crispier edges, bake a little longer.
- Remove the cookie bars from the oven and let them cool in the pan on a wire rack. Use the parchment paper sling to lift them out of the pan. Cut into pieces with a sharp knife.
- Store the cookie bars in an airtight container at room temperature for up to 3 days.
Notes
The initial quantity of butter is larger than the amount of brown butter used in the recipe to account for water loss during browning. If you are scaling the recipe, note that pan sizes and cooking times in the method do not scale automatically; only the ingredient quantities in the list will adjust.