Ingredients :

• The potatoes — Exclusively choose a waxy variety—Charlotte, Fingerling, or Baby potatoes. Floury potatoes (like Russets or Bintje) will turn into mash at the slightest stir. Waxy flesh is non-negotiable here.
• Canned tuna — Canned tuna in water is a must. Tuna in oil is excellent on toast, but in an already dressed salad, it adds unnecessary fat. Choose a brand whose smell you know—it really changes the final result.
• Mustard vinaigrette — This is what does all the work. The mustard emulsifies and gives body, the lemon lightens it up, and the mild vinegar rounds it all out. Whisk well until the texture becomes slightly creamy—you’ll see the change.
• Fresh herbs — Parsley and chives aren’t just for decoration. They bring a green, slightly peppery note that keeps the salad from being bland. Dried? They don’t work the same way. Fresh only.