• ¼ white onion, thinly sliced
  • Small red onion, thinly sliced
  • 2 Tbsp extra-virgin olive oil
  • 1 Tbsp red-wine vinegar, plus more to taste
  • ¼ tsp salt
  • Black pepper to taste
  • 1 (6 oz) can tuna in olive oil
  • Lemon juice, to taste
  • 2 Kaiser rolls
  • Lettuce leaves
  • 8 tomato slices
  • 1 egg, hard-boiled

DIRECTIONS:

1. Combine onions with olive oil, 1 Tbsp red-wine vinegar, salt, and black pepper in a bowl; marinate 5 minutes.

2. Mix in tuna, including the oil. Season with lemon juice, more red-wine vinegar, salt, and pepper to taste.

3. Cut kaiser rolls in half crosswise; place lettuce leaves on bottom half. Top each with 4 tomato slices, half the tuna mixture, and 3 slices hard-boiled egg. Add pitted Niçoise olives, if desired.

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