Whisk the eggs and sugars

• In a bowl, whisk the eggs, egg yolk, powdered sugar and brown sugar vigorously until smooth and the powdered sugar has completely dissolved.
• This step is what gives the shiny crinkly top.

Add the wet ingredients

• Add the melted butter, oil and coffee powder.
• Whisk until well combined.

Fold in the dry ingredients

• Add the flour, cocoa powder and chocolate chips.
• Fold gently with a spatula, do not overmix.

Bake the brownies

• Transfer the batter to a parchment lined 8x8 pan.
• Bake in a preheated oven at 180 °C until the edges are set and the center still looks a little soft.
• Underbaking is better than overbaking.

Cool and slice

• Cool completely before slicing.
• For the best texture, chill in the fridge.