Several years ago my husband and I flew to Arcachon, a small, seaside summer playground in southwestern France, just over an hour’s drive west from Bordeaux, for the wedding of a friend. Arcachon Bay, known for its oysters and cockles, was the ideal escape for a week of drinking wine and lounging by the sea, and we easily got the lay of the land.My favorite day of our trip started with a short ferry ride across the water to Saint-Jean-Cap-Ferrat, a sleepy resort village on the tip of the peninsula, complete with vacationers bicycling to the market in navy stripes and a smattering of simple seafood restaurants near the area’s fabled oyster beds. When we arrived for lunch, at low tide, the fishing boats on the bay had sunk into the sand on all sides of us, but as the tide rose, so did the boats, and by the end of our meal they bobbed in the gentle waves.We found a table outside and ordered from the limited menu: a few dozen raw oysters, bowls of tiny poached shrimp, a plate of crudités with herby aioli, garlicky escargots and tins of anchovies and sardines in their oil, butter and lemon slices on the side. I relished those tinned fishes, sopping up the briny oil with my bread, spreading and mashing silvery sardines and saline anchovies on top, slurping the oysters and sipping cool white wine. Back home in New York, I couldn’t get the flavors out of my head. That’s when I discovered anchoïade, a rustic Provençal spread made with tinned anchovies, vinegar or lemon, and garlic. My version includes chile flakes and a big pinch of lemon zest, but its essence remains the same. Making and using it—on seafood, on buttered bread, even as a condiment for steak—scratches that daydreamy itch for the flavors of the French seaside.