Chocolate Chunk Espresso Muffins

When I dream of chocolate muffins, these are what I dream of. A moist and tender sour cream batter with big chunks of melted dark and milk chocolate. All nestled under a blanket of salty, crisp chocolate streusel and sweet coffee mascarpone cream. I think they're quite beautiful with their rough rocky surface and different shades of cocoa. My perfect chocolate muffin.