Ingredients :

• Waxy potatoes — Charlotte, Ratte, Belle de Fontenay — take any from this family. The important thing is that they don’t fall apart during cooking. A starchy potato will turn your salad into a lumpy mash. Absolutely avoid them.
• Canned tuna — In water or in oil, it depends on your preference. Oil adds richness, while water is lighter. In both cases, drain it very well — not halfway — or the salad will get watery and dilute the flavors.
• Red onion — No white or yellow onions here. Red onion has a milder bite and a color that contrasts beautifully against the pale potatoes. If you find it too sharp, soak it for 10 minutes in cold water — this removes the bitterness without killing the taste.
• Black olives — Choose olives with character, not those flavorless canned slices. Kalamata olives or black olives marinated in oil are a different world. They provide a slight bitterness that balances the tuna perfectly.