Tuna Burger

Method

1. Cut the tuna into slices, then into small pieces.
2. Chop the tuna finely with a knife or mezzaluna.
3. Lightly whip one egg white until semi-stiff peaks.
4. To the chopped tuna, add the semi-whipped egg white, finely chopped anchovies, capers, and salt. Mix well. Add more egg white if needed to bind.
5. Form the mixture into a patty with oiled hands. Wrap in plastic wrap or parchment paper and refrigerate for 10 minutes.
6. Caramelize the onion: in a pan with olive oil, add sliced onion, a pinch of sugar, white vinegar, a garlic clove, and chili. Cook until soft and golden.
7. Add the escarole to the same pan and cook until wilted and tender. Set aside.
8. Toss pre-roasted peppers with oregano, olive oil, and salt for the marinated peppers.
9. Toast the burger buns in a pan with a little oil until golden.
10. Prepare two sauces: a green sauce with parsley and sun-dried tomato; a spicy sauce with chili oil.
11. Cook the tuna patty: in a pan with olive oil, sear on both sides until nicely browned on the outside, leaving the center slightly rare.
12. Spread mustard on the inside of the toasted buns.
13. Assemble: on the bottom bun, spread some sauce, then escarole, then the tuna patty, then marinated peppers, then caramelized onion, then more sauce. Close with the top bun.