The simple but exquisite ham-and-butter sandwich on a french loaf was first wrapped in waxed paper and then a towel. The "secret ingredient," according to Fisher, was "to sit gently but firmly upon this loaf for at least 20 minutes."

This isn't just hyperbole: Time spent under weight marries the ingredients together more intimately than just slapping them between slices of bread, and something magical happens.

The classic version of this is pan bagnat (pahn bahn-YAT), a specialty of the south of France — a loaf stuffed with goodies an hour or two before eating and weighted down to allow a vinaigrette dressing to penetrate the bread.

The name means "bathed bread" — the sandwich is often used to celebrate the first pressing of olive oil — and it's a sumptuous tradition worth borrowing.

Weighting will ensure that flavorful drippy ingredients such as tomatoes and vinaigrette will penetrate and soften the loaf you choose. Letting the smashed sandwiches rest for an hour or more, whether you're traveling or not, allows the ingredients to get to know one another.

Serious sandwiches begin with good bread. For these grown-up sandwiches, look for the hero loaf — the one with a firm but tender crumb and a stalwart crust — French or Italian loaves in round, long or individual rolls such as ciabatta, focaccia or campagne.

Vary ingredients as you wish.

Let your pan bagnat exude multiple flavors

Classic pan bagnat

• 1 round crusty loaf, or 4 crusty French or Italian rolls
• 3 tablespoons red wine vinegar
• 2 cloves garlic, crushed
• 1 teaspoon Dijon-style mustard
• Pinch of sugar
• 1/2 teaspoon salt
• 1/2 teaspoon freshly ground black pepper
• 1/2 cup extra-virgin olive oil
• 2 medium ripe tomatoes, cored and thinly sliced
• 1 small red onion, thinly sliced
• 12 fresh basil leaves, rinsed and dried
• 1 (6-ounce) can light or dark tuna, packed in olive oil, drained
• 16 black dry-cured olives, pitted (or one-half cup olive tapenade)
• 2 cups mixed baby salad greens (mesclun)

Slice bread or rolls in half horizontally and set aside. In small bowl, whisk together vinegar, garlic, mustard, sugar, salt and pepper; slowly whisk in the oil.

Brush a little vinaigrette onto each cut surface of bread. Layer tomatoes onto bottom of bread, season with a little salt and pepper.

Drizzle a spoonful of vinaigrette over tomatoes. Layer on onion and basil, spoon the tuna on top, drizzle with vinaigrette.

Add olives (if using tapenade, spread on cut surface of bread top) and greens, drizzle with any remaining vinaigrette. If desired, add a grind of the pepper mill.

Place top half of bread on, and wrap sandwich well, first with plastic wrap, then with a clean kitchen towel. Place a weight (like a heavy pot lid) and let stand at room temperature for one hour.

For traveling, place in bottom of hamper or cooler and weigh down with plates. Remove weight and, if not using individual rolls, cut loaf into four quarters to serve four.

Variations: Aim for a savory balance that includes at least two or three flavor elements and textures: smoky (bacon), mellow (avocado), pungent (goat cheese, onion), piquant (hot peppers), smooth (egg, cheese), crunchy (cucumber, greens), salty (olives, anchovies, salami).

Vinaigrette: For a robust, tart vinaigrette, use one part vinegar to three parts oil. For a mellower, smoother mixture, increase the oil to four parts. It's a matter of personal taste — either style is good on these sandwiches.

To make vinaigrette, whisk together all seasonings with the vinegar (everything except the oil) first, then slowly whisk in the oil. Taste and adjust seasoning. Store covered in the refrigerator; bring to room temperature before using.