Soak dried chillies in 1/2 cup of boiling water until soft.
Place the chillies (discard the water), coriander seeds, cumin seeds, black peppercorns, ginger garlic paste, sweet soy sauce, and vinegar in a food processor. Cover and blend into a coarse paste. Set the paste aside.
Heat olive oil in a deep skillet over medium heat. Add the curry leaves and onions, and cook, stirring until the onions are soft and translucent, about 5 minutes.
Add the blended paste and cook until aromatic, about 8 to 10 minutes. The paste is cooked when the oils separated on the surface and is reddish brown colour.
Add the coconut cream, 1 cup of water, and turmeric and bring to a boil. Raise the heat to medium, and add the seafood. Cover and simmer until the mussels open, about 3 to 4 minutes. Discard any mussels that are closed.
Add the butter and salt and mix well. Garnish with fresh cilantro and serve immediately.