Gather all the ingredients.
Melt chocolate and butter in a saucepan or microwave or double boiler.
In a large bowl beat egg with a mixer till it becomes light, fluffy, and double the volume.
Add sugar, chocolate-butter mix, and vanilla extract in the beaten eggs. Mix with a mixer om medium speed for 2 minutes.
Sift in all the dry ingredients and mix with a spatula.
Add chopped chocolate and mix with spatula.
Refrigerate the dough for 30 minutes.
Line a baking tray with parchment/butter paper.
Preheat the oven to 180℃ (356℉).
Scoop cookie dough with an ice-cream scooper or a spoon and place them on baking tray with little distance between them.
Bake for 10-15 minutes at 180℃ (356℉).
Take them out when cracks begin to appear and when pressed leaves no imprint.
Immediately after taking them out from oven remove them from baking tray and place on a wire rack to completely cool down.
After cooling store them in airtight container at room temperature
