Hard boil the eggs, then peel and separate yolks from the whites.
Drain the tuna well.
Add the egg whites, tuna, celery, spring or red onions and dill pickle to a bowl.
In a separate bowl, mix together the Greek yoghurt, Dijon mustard, egg yolks, garlic powder, salt and pepper.
Pour the sauce over the tuna mixture and stir until well combined.
Serve on toasted sourdough, in a sandwich, on crackers, or enjoy it straight from the bowl.
