Start by preparing the quick pickled onions. Peel the onion, cut in half and thinly slice, then pack into a clean large glass jar and set aside. Place the remaining ingredients in a small saucepan and cook over medium heat until all the sugar is dissolved and the mixture reaches a simmer. Pour the hot pickle liquid in the jar over the onions, pressing the onions down if necessary until submerged. Leave at room temperature until cool. You can use them once cooled, and store them in the fridge for up to 2 weeks.

For the tuna MAYU sarmie, combine the NOMU MAYU, celery, parsley, chopped pickles and mustard and season to taste with salt, pepper and lemon juice.

Lightly toast your bread. Spread a generous amount of the MAYU mixture on two slices and top with tuna. Season to taste, then add some pickled onions and plenty of fresh rocket. Sandwich with a second slice of bread and enjoy!

Tip: This recipe will make enough for about 2 sandwiches, depending on how generous you are with the fillings. Any leftover tuna and MAYU sauce can be enjoyed in a salad with crisp iceberg lettuce, cucumber, tomato and sunflower seeds.

Toasting the bread stops it from getting too soggy from the tuna and adds some extra crunch to contrast the soft filling.