Olives, tomatoes, hard-cooked eggs, fragrant herbs, and a mustardy vinaigrette—not mayo—are the components that put this Provençal staple on the map. Our version of pan bagnat, a classic Provençal sandwich that shares many of the same ingredients as salade niçoise, features a crusty baguette packed with high-quality jarred tuna, olives, capers, tomatoes, hard-cooked eggs, fresh herbs, and a mustardy vinaigrette. We used a large baguette, which offered enough surface area to accommodate the filling, and removed the inner crumb from the bottom half of the loaf to create a trough that provided more space. Processing the olives, capers, anchovies, and herbs into a coarse “salad” helped those components hold together, and applying the salad in two layers in the sandwich distributed its assertive flavors. To control the bread's moisture absorption, we brushed the cut surfaces with olive oil, which helped waterproof it. Stirring the vinaigrette into the olive salad thickened the dressing so that it didn't oversaturate the crumb, and we also thoroughly drained the tuna and tomato slices to remove much of their liquid. Tightly wrapping the sandwich halves with plastic wrap and pressing them for at least an hour under a heavy Dutch oven tamped down the filling so that the whole package was compact enough to bite through.