Seared Tuna Sandwich with Balsamic Onions

4 people
Prep Time:
00h 05
Cook Time:
00h 10

Tuna sandwiches on the brain? Enjoy freshly-made tuna in less than 20 minutes, with a garlicky seasoning you won’t find in a can.

Credit: This inspiring recipe is brought to you by Robyn Webb. You can view this recipe on the My Recipes website. 

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Ingredients and Method


  • 2 teaspoons butter
  • 2 cups onions, vertically sliced
  • 1 1/2 tablespoons balsamic vinegar
  • 1/4 teaspoon dried thyme
  • 1 tablespoon all-purpose flour
  • 1/2 teaspoon kosher salt
  • 1/4 teaspoon garlic powder
  • 1/4 teaspoon freshly ground black pepper
  • 4 tuna
  • 4 whole wheat hamburger buns
  • 4 curly leaf lettuce leaves
  • 4 slices tomatoes


  1. Melt butter in a medium skillet over medium-high heat. Add onion; sauté 5 minutes. Stir in vinegar and thyme; cover and cook 5 minutes, stirring occasionally.
  2. While onion cooks, combine flour, salt, garlic powder, and pepper in a shallow dish. Dredge fish in flour mixture. Heat a large nonstick skillet coated with cooking spray over medium-high heat. Add fish; cook 3 minutes on each side or until desired degree of doneness.
  3. Spread 1 teaspoon mustard over top half of each bun. Layer 1 lettuce leaf, 1 fish steak, 1 tomato slice, and 1/4 cup onion mixture on bottom half of each bun. Top with top halves of buns.