Combine the ingredients in a bowl, mixing well. Then, portion the mixture into individual dipping plates as needed.
Simply add the listed ingredients directly to a serving plate. If you're serving a larger group, prepare individual dipping plates for each person instead. (This is how my mum did it at her restaurant – no need to mix a large batch in a bowl.)
Combine the first four ingredients listed above in a bowl, stirring until the sugar dissolves.
Using a spoon (a 1 Tbsp measuring spoon works well), portion the sauce onto individual dipping plates as needed.
Add the sliced onion to the sauce and place wasabi paste on the side of the plate.
