Soak the fresh mussels in cold water for about 20 minutes to help them expel any sand or grit. Scrub the shells thoroughly under running water, removing any beards, and discard any that remain open or have cracked shells.

While the mussels are soaking, finely chop the garlic, half an onion, and one ripe tomato. Set these aside.

In a large sauté pan, heat the vegetable oil and sesame oil over medium heat for 1-2 minutes until shimmering.

Add chopped garlic, onion, and grated ginger to the pan and sauté for approximately 3 minutes until the onion is soft and translucent.

Stir in white miso paste and chopped tomato, cooking for an additional 2 minutes until well combined.

Pour in broth, fish sauce, and mirin, bringing the mixture to a gentle boil, stirring occasionally.

Add cleaned mussels to the boiling broth, cover with a lid, and simmer for 8-10 minutes until they open.

Stir in cooking cream and butter, allowing it to melt for 1 minute. Adjust seasoning if necessary.

Garnish with chopped chives and chili oil or slices of fresh chili pepper, then serve immediately with toasted crusty bread.