Prepare the pan and oven

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

Melt the chocolate with the oil

• Gently melt the chopped dark chocolate with the oil in a saucepan over low heat, stirring until smooth.
• Remove from the heat and let cool slightly.

Whisk the sugars and eggs

• Whisk the granulated sugar, brown sugar and eggs in a mixing bowl until pale and thick.
• Stir in the vanilla extract.

Combine the wet mixtures

• Pour the melted chocolate and oil into the egg mixture.
• Whisk until completely smooth and glossy.

Fold in the dry ingredients

• Add the flour, sifted cocoa powder and salt.
• Fold gently with a spatula until just combined, without overmixing.
• Fold in the chocolate chips.

Bake the brownies

• Spread the batter evenly in the prepared pan.
• Bake until the edges are set and the center is slightly soft.

Cool and cut

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