Tuna Melt - Sandwich Recipe

Prepare tuna

Drain canned tuna thoroughly and transfer to a medium bowl. Use a fork to break into flaky pieces.

Add mayonnaise, Greek yogurt, and Dijon mustard to the bowl. Stir to combine until creamy.

Mix in minced red onion, diced celery, chopped capers, and lemon juice. Season with 1 tsp salt and 1/2 tsp freshly ground black pepper. Taste and adjust seasoning as needed. Refrigerate while you prepare the other components so flavors meld.

Roast garlic

Preheat oven to 400°F (200°C). Slice the top off the garlic head to expose the cloves, drizzle with 1 tsp olive oil, wrap in foil and roast for 35-40 minutes until soft and golden. Let cool slightly, then squeeze out the soft cloves into a small bowl and mash into a smooth paste. Set aside.

Caramelize onions

Meanwhile, heat 1 tbs butter and 1 tbs olive oil in a large skillet over medium-low heat. Add the thinly sliced onion and 1/4 tsp salt. Cook slowly, stirring every few minutes, lowering heat if they brown too quickly. After 15 minutes, sprinkle 1/2 tsp sugar over the onions to encourage caramelization. Continue to cook another 10-15 minutes until deep golden-brown and sweet. Remove from heat and set aside. Reserve 2 tbs of the caramelized onions to use on sandwiches; remaining can be refrigerated for another use.

Combine roasted garlic paste with 2 tbs of the reserved caramelized onions (optional) and taste. You should have about 2 tbs garlic-onion paste to spread on the bread.

Increase oven to 425°F (220°C) or use same 400°F if preferred. Toss halved tomatoes with 1 tsp olive oil, 1/4 tsp salt and 1/4 tsp black pepper on a small rimmed baking sheet. Roast for 12-18 minutes until they soften, concentrate, and edges begin to blister. Remove and let cool slightly.

Prepare bread

Butter one side of each of the 4 bread slices evenly (about 1/2 tbs butter per slice). Heat a large skillet or griddle over medium heat.

Place buttered-side down 4 bread slices in the hot skillet. Spread about 1/2 tbs roasted garlic paste on the untoasted (top) side of each slice that will be the interior/top when assembled. Top the untoasted (top) side with a thin layer of tuna salad (about 3 oz / 3 tbs per sandwich), followed by 2-3 roasted tomato halves, a few leaves of lettuce, and 2 oz (about 2 slices) fresh mozzarella. Close each sandwich with the buttered bread slice (butter side out).

Cook sandwiches in the skillet over medium heat, pressing gently with a spatula or using a sandwich press. Cook 3-4 minutes per side, flipping once, until bread is golden brown and mozzarella is melted. If mozzarella isn't melting, cover skillet with a lid for 1-2 minutes to trap heat.

Once toasted and cheese melted, remove sandwiches, let rest 1 minute, then cut in half. Drizzle a little balsamic glaze over the tuna or tomatoes if desired. Serve immediately.