Grilled Rare Tuna Salad With Basil-Tapenade Vinaigrette

Ingredients

• 8 ounces fresh tuna steak
• kosher salt and freshly ground black pepper
• 1 tablespoons dried herbes de provence
• about 1 cup olive oil
• 2 tablespoons capers in brine, rinsed and pressed dry between paper towels
• 2 tablespoons homemade or store-bought black olive tapenade
• 2 tablespoons white wine vinegar
• 1/2 to 1 small garlic clove, grated, about 1/4 to 1/2 teaspoon
• 10 basil leaves, thinly sliced, plus extra for the salad
• 1 beefsteak tomato, thinly sliced
• 1 head bibb lettuce, torn
• 1 lemon, quartered