Ingredients

• 6 tablespoons mayonnaise
• 5 tablespoons minced fresh basil
• 1 teaspoon grated lemon peel
• 3 tablespoons olive oil
• 1 tablespoon fresh lemon juice
• 4 5- to 6-ounce skinless salmon fillets (each about 3/4 inch thick)
• 8 bacon slices
• 1 small red onion, sliced
• 8 1/2-inch-thick sourdough or country-style white bread slices (each about 5x3 inches)
• 8 tomato slices
• 8 lettuce leaves

Instructions

1. Mix mayonnaise, 2 tablespoons basil and lemon peel in small bowl to blend. (Can be made 1 day ahead. Cover and chill.)
2. Mix remaining 3 tablespoons basil, olive oil and lemon juice in large glass baking dish. Add salmon to oil mixture; turn to coat. Cover; chill 1 to 4 hours.
3. Cook bacon in heavy large skillet over medium-high heat until crisp. Using tongs, transfer bacon to paper towels to drain. Add onion to drippings in skillet. Sauté until onion is tender and beginning to brown, about 5 minutes.
4. Prepare barbecue (medium-high heat). Grill fish until just opaque in center, about 3 minutes per side. Grill bread just until golden, about 2 minutes per side. Spread mayonnaise mixture over 1 side of bread slices. Top each of 4 bread slices with 2 bacon slices, 2 tomato slices, 1/4 of onion, 1 salmon fillet and 2 lettuce leaves. Cover with remaining bread slices.