Prepare the mussels

• Scrub the mussels and remove the beards
• Steam or boil the mussels until they open, then discard the empty half shells

Make the dynamite sauce

• Mix the mayonnaise, sriracha, soy sauce, sesame oil and grated garlic in a bowl
• Stir in the masago

Top the mussels

• Arrange the mussels on the half shell on a baking tray
• Spoon the dynamite sauce generously over each mussel

Bake

• Bake until the topping is hot and lightly browned

Serve

• Scatter the sliced spring onion over the mussels and serve hot