Preheat the oven to 180°C.
Melt the chocolate and butter together using a double boiler.
In a bowl, mix sugar and eggs.
Add the melted chocolate and butter mixture and mix well.
Sift the flour and salt into the mixture and gently combine.
Pour the batter into a baking pan.
Bake at 180°C for 20–25 minutes.
Let it cool completely, then cut into desired sizes.