Mediterranean Tuna Sandwich | Saveur

Ingredients

• 1 (4-oz.) can tuna, drained
• 3 tbsp. roughly chopped cornichons
• 3 tbsp. roughly chopped walnuts
• 2 tbsp. olive oil
• 2 tbsp. whole grain mustard
• Kosher salt and freshly ground black pepper, to taste
• 2 slices multigrain bread, toasted
• Butter lettuce, for serving