Tonno Rosso Sandwich

True to the word "Rosso", red tuna, red onion and red radicchio are prepared into a Sicilian aperitivo.

Ingredients

• 200 g red onions
• 300 g fresh fillet of tuna
• 500 ml white wine vinegar
• 500 g radicchio
• 1 Spritzer balsamic vinegar
• 1 focaccia or any good white bread
• 50 g caciocavallo cheese, coarsely grated (you can substitute Parmesan cheese if you can't find caciocavallo)
• 10 green salad leaves
• etwas salt, olive oil
• 1 Handvoll garlic
• etwas fresh thyme

Steps

1. Slice the onions and soak them in the white wine vinegar for 24 hours. Wash the radicchio well, cut it in half and roast it in a grill pan without oil. Then cut into slices and season with oil, salt, chopped garlic, thyme leaves, stripped from their stalks, and a splash of balsamic vinegar.
2. Season the tuna with oil and a little salt and grill in a very hot grill pan for just under 1 minute on each side. Make sure that the tuna is nicely roasted on the outside and still raw on the inside. Set aside to cool and slice very thinly.
3. Cut the focaccia lengthwise or cut nice slices from the white bread.
4. Season the bread with salt and olive oil.
5. When assembling the sandwich, put the radicchio in first as a base before adding the cheese. Melt it briefly in the hot oven, then pile on the thinly sliced tuna along with the onions (removed from the vinegar and drained) and lettuce. Put the other half of the bread on top and cut into small sandwiches.