An easy and simple but delicious tuna sandwich that is the perfect lunchtime meal to keep you going throughout the day. Perfect for the kids lunchbox!
With a fork mix onion, celery, mayonnaise and mustard. Season with salt and pepper.
Mix in the tuna until well combined. Season with salt and pepper,
Slice fresh bread and scoop the mix onto the bread and serve.
*OPTIONAL* Can be made in advance and cover in fridge for three days