1. Preheat the oven to 200°C (425°F). Line a muffin tin* with paper liners (tulip papers)*. The recipe is for larger muffins – if you only have regular paper liners, you need more. Set aside.

2. Chop the chocolate. Set aside about 7 oz. (200g) of the chocolate and add the rest to a heatproof bowl along with the butter. Melt in the microwave or over a pot with simmering water. Mix until smooth and let cool down a bit. Add the sugar, sour cream, vanilla extract and eggs and mix until well combined. Add the flour, cocoa powder, baking soda, and salt to a large bowl and mix. Next, add the chocolate mixture and fold it in until well combined. Add about 2/3 of the chopped chocolate you kept aside and fold it in. Fill into the tulip paper liners and sprinkle with the remaining chopped chocolate.

3. Place in the oven and bake for 5 minutes, then reduce the heat to 175°C (350°F) and bake the muffins for another 17-20 minutes or until a toothpick inserted into the center comes out clean. Take out of the oven and let cool down completely on a wire rack.