Preheat the oven to 180°C
In a bowl, whisk together eggs, brown sugar, yogurt, and melted butter
Add flour, cocoa powder, baking powder, and baking soda
Mix just until combined, do not overmix to keep the muffins soft
Fold in dark chocolate and chocolate chips
Pour the batter into muffin cups and bake for 30 minutes at 180°C
Let cool slightly before serving
