- Make sushi rice: Rinse and drain rice 3 times or until water runs clear. Place rice in sieve over a bowl. Set aside for 10 minutes to drain.
- Place rice and 2 cups cold water in a small saucepan over medium heat.
- Cover. Bring to the boil. Reduce heat to low. Simmer, covered, for 12 minutes or until water has been absorbed. Remove from heat. Stand, covered, for 10 minutes.
- Transfer rice to a large ceramic dish. Using a spatula, stir rice to break up lumps. Gradually add seasoning, lifting and turning rice, until rice has cooled.
- Place egg, onion and mayonnaise in a medium bowl. Stir to combine.
- Place nori sheets, shiny-side down, on bench. Using damp fingers, spread 1/4 the rice mixture over each nori. Spread egg mixture over 1 nori sheet.
- Place remaining rice-covered nori sheet over egg mixture, rice-side down.
- Press down to secure. Cut into 4 even squares cut each square into 4 triangles and repeat again. Serve with soy sauce and pickled ginger.