Preheat oven to 350°F/180°C.
Line baking pan with parchment paper.
Melt the dark chocolate in a microwave-safe bowl, stirring every 30 seconds until smooth.
Transfer the chocolate to a large bowl, add oil, and mix well.
Stir in sugar, eggs, and salt. It is important to work quickly so that the eggs do not harden from the heat of the chocolate.
Add flour and mix until everything is combined.
Spread batter into the prepared pan and flatten the mixture with a spatula. The mixture will be very thick, and that is OK.
Bake for 18 to 25 minutes. Do not overbake. Brownies should be puffed and beginning to crack at the edges, but still soft to the touch. (a toothpick stuck in the center comes out with moist chocolate crumbs).
Cool to room temperature.
Slice into squares and enjoy!