Preheat and prepare the pan

• Preheat the oven to 175 °C.
• Line a square baking pan with parchment paper.

Beat the eggs and sugar

• Whisk the eggs and sugar together until the sugar is completely dissolved.
• Keep beating until the mixture turns pale and glossy.

Add the butter

• Pour in the melted butter and whisk until fully combined.

Fold in the dry ingredients

• Sift the cocoa powder and flour over the wet mixture.
• Fold gently until the batter is smooth and lump-free.
• Optionally fold in the chocolate chips.

Bake the brownies

• Pour the batter into the prepared pan and spread evenly.
• Bake until the center is still fudgy.

Cool and slice

• Let the brownies cool completely in the pan.
• Slice into squares and serve.