Tuna Melt Panini with Caramelized Onions and Swiss Cheese

By AislePrompt Editorial · ·

How this recipe was made — this recipe was drafted by AislePrompt's AI-assisted pipeline from technique templates and USDA-sourced nutrition data, and published by AislePrompt Editorial — see how AislePrompt recipes are drafted and published.

A warm panini filled with creamy tuna salad, sweet caramelized onions, and melted Swiss cheese pressed to golden perfection. This American-inspired sandwich and wrap recipe, ready in about 30 minutes, pairs canned tuna in water, mayonnaise, Dijon mustard for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 550 calories and feeds 1, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 20 min Cook: 10 min Serves 1 American cuisine 550 cal/serving
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Ingredients

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Instructions

  1. Step 1: Heat 1 tbsp unsalted butter in a skillet over medium-low heat. Add 1 small thinly sliced red onion and cook gently, stirring occasionally, for 15 minutes until onions are soft and golden brown and caramelized. Season with 1/8 tsp black pepper and a pinch of salt.
  2. Step 2: In a bowl, combine 5 oz drained canned tuna, 2 tbsp mayonnaise, 1 tsp Dijon mustard, and 1/4 tsp salt. Mix until creamy but still slightly chunky.
  3. Step 3: Preheat panini press or grill pan over medium heat.
  4. Step 4: Brush 2 slices sourdough bread lightly with 1 tsp olive oil on one side each. On the un-oiled sides, spread the tuna mixture evenly on one slice. Top with caramelized onions and then 2 slices (about 2 oz) Swiss cheese.
  5. Step 5: Close sandwich with the other slice of bread, oil side up. Place in the panini press and cook for 3-4 minutes until bread is golden brown and cheese is melted, or grill in a skillet pressing sandwich with a heavy pan, flipping halfway.
  6. Step 6: Remove from heat, let rest for 1 minute, then cut diagonally and serve hot.

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