A sandwich that improves with age? Oui! The name of this classic French tuna sandwich means "bathed bread," a reference to brushing the baguette with olive oil to ward off sogginess.
For this sandwich or any recipe where tuna isn't doused in mayo or baked with noodles, it's worth splurging on a high-quality, imported brand. (One we love: Conservas Ortiz, a Spanish tuna available at specialty stores such as Whole Foods or online.) This kind of tuna is line-caught, delicately poached and hand-packed in olive oil so it stays firm and flakes beautifully. The oil keeps the fish moist and silky and adds a rich, almost buttery flavor. You could even use the olive oil from the can to bathe your bread in Step 1 of the recipe---it's that good.
White anchovies are more mild in flavor than regular canned anchovies, but if you're not a fan, just skip them.
Drain and rinse one 15-ounce can chickpeas. Mash slightly. Thinly slice 1 bulb fennel, removing the woody core. Compose the sandwich as follows: potatoes, cucumber, chickpeas, lemon juice, tomato, eggs (omit for a vegan choice), sliced fennel, olives and capers. Continue as directed in Step 3.