Roughly break half of the chocolate (150 g) and melt it with 125 g butter over a hot water bath (see tips & tricks). Stir occasionally.
In the meantime, roughly chop the remaining chocolate (150 g).
In a mixing bowl, beat 2 eggs, 1 pinch salt, 75 g muscovado sugar and 75 g white sugar for about 6 min until fluffy and the sugar has completely dissolved.
Preheat the oven to 175 °C (350 °F), conventional oven (top and bottom heat).
Add the melted chocolate / butter to the mixing bowl and stir in briefly.
Mix 175 g all-purpose flour, 25 g cocoa powder and 1 level tsp baking powder in a small bowl and add to the dough in the mixing bowl.
Briefly stir in with a whisk and fold in the prepared chopped chocolate.
Line 2 baking sheets with parchment paper. Using a cookie scoop or an ice cream scoop (see tips & tricks), scoop out about 12 to 18 balls and spread them out with space between them on the two baking sheets.
Flatten the balls slightly with a tablespoon.
Bake the baking sheets one after the other for about 10 - 15 min (depending on size and thickness). (see tips & tricks)
Let cool and enjoy.