Pre-heat the oven at 180°C and line a tray with baking paper.
In a medium bowl, mix all the dry ingredients together.
Finely chop the chocolate.
Melt the butter in a saucepan on low heat, then remove from the heat. Add the chopped chocolate and mix until melted and combined.
Combine the eggs and sugar in a mixing bowl, beating them on medium to high spead for about 5 minutes.
Once the chocolate and butter mixture has slightly cooled down, pour it over the eggs, using a rubber spatula to fold the chocolate in. Add the dry mixture and fold it in with the spatula, just until combined. Try to avoid over-mixing.
Use a ice-cream scoop or a large spoon to measure equal amounts of batter. Scoop balls of mixture onto the baking sheet, spacing them at 5 cm apart, as they will spread while baking. Sprinkle the cookies with flaky salt if desired.
Quickly transfer the baking sheet to the oven and bake the cookies for 10-12 minutes, until the tops of the cookies are crinkled. They will crinkle more once removed from the oven. Allow them to cool down for about 15-20 minutes before transfering from the tray to a plate.