Niçoise salad is a French composed salad from Nice, on the Mediterranean coast, built from tomatoes, boiled new potatoes, tuna, Niçoise olives, hard-boiled eggs, and anchovies, dressed with olive oil, lemon juice, and Dijon mustard, and arranged on the plate rather than tossed.
The salad developed in the late 19th century from a simpler dish of tomatoes, anchovies, and olive oil, gradually adding potatoes, tuna, and eggs as it became associated with the broader Provençal table. A composed salad differs from a tossed salad mainly in presentation: the ingredients are laid out separately on the plate so each component stays distinct, rather than mixed together.
It's typically served chilled or at room temperature, especially in warmer months, and variations add green beans or artichoke hearts, substitute fresh seared tuna for canned, or swap in grilled chicken or beef; purists debate whether cooked vegetables like potatoes and green beans belong in an 'authentic' Niçoise salad at all, since the earliest versions used none.