Cook and season the rice

• Rinse the sushi rice until the water runs clear, then cook it.
• Warm the rice vinegar, sugar and salt until dissolved and fold through the cooked rice.
• Let the rice cool to room temperature.

Make the sushi bake filling

• Mix the drained tuna with mayonnaise, sriracha, soy sauce and softened cream cheese.
• Fold in the sliced spring onion.

Bake the sushi bake

• Spread the seasoned rice in a baking dish and top with the tuna mixture.
• Scatter the shredded mozzarella over the top.
• Bake at 200 °C until the cheese is melted and bubbling.

Shape the onigiri

• Let the bake cool slightly, then scoop portions and press into triangles or balls.
• Wrap each onigiri with a strip of nori.
• Sprinkle with toasted sesame seeds and serve.