Pan Bagnat (French Tuna Sandwich) Recipe

Ingredients

• 1/2 small red onion, thinly sliced
• 2 (5-ounce) cans oil-packed tuna fish
• 1/4 cup olive oil
• 2 anchovy fillets, finely chopped
• 1/4 cup pitted Nicoise or Kalamata olives
• 1 to 2 tablespoons red wine vinegar
• 2 10-inch baguettes, or 1 full-sized baguette, cut in half (see Recipe Note)
• 1 garlic clove, peeled
• 1/2 teaspoon salt
• 1/8 teaspoon pepper
• 2 hardboiled eggs , sliced
• 2 tomatoes, sliced
• 12 large basil leaves