1. Melt the butter (either in a small pot on the stove or in the microwave) and let it cool down again. Chop the chocolate coarsely, you want not-too-small pieces.

2. Add the sugars and melted butter to a large bowl and mix until the mixture gets creamy and light – takes about 1-2 minutes. Add the egg and mix it in well. Next, add the vanilla extract and mix it in. Mix the flour with baking soda, and salt and add to the bowl, and mix until just combined. Add about 2/3 of the chopped chocolate and fold in. Place the dough in the fridge for at least 30 minutes.

3. Preheat the oven to 180°C (360°F). Line a baking sheet with baking parchment. Use a cookie scoop or two tablespoons and place dough portions (about 2 tbsp. each) with enough space (about 4cm) on the baking sheet. Add some more chopped chocolate on the dough and bake the cookies for about 11-12 minutes. Do not overbake them! The edges of the cookies should be firm, but the center still a bit soft. Take them out of the oven and let them cool down on the baking sheet for some time, then transfer them to a wire rack and let them cool down completely.