• Preheat oven to 180 ℃. Line the baking sheet with parchment paper.
• Add the dark chocolate, butter and sugar to a pan, and melt on low heat. Stir frequently so the chocolate doesn't burn, and melt until it's smooth.
• Transfer the mix to a bowl, and leave to cool for 10 minutes.
• Add in the eggs, one at a time, stiring in fully each time.
• Add in the flour, cocoa powder, and stir until combined.
• Pour the mixture into the tin, and then sprinkle over the chocolate chips.
• Bake the brownies in the oven for 30-35 minutes.
• Leave the brownies to cool in the tin fully.

Tip:

• To have the best result, place the brownies into the fridge over night.