A recipe from Christian Parra that I happily used:
[usr 2]
Preparation of the piperade:
Scald the tomatoes to peel them more easily. Then squeeze them to squeeze out the water from the vegetation and the pips. Crush them. Peel and finely slice the onions. Peel and crush the garlic cloves. Cut the peppers in half lengthwise. Seed them. Cut them into three or four pieces.
Heat the olive oil in a sauté pan. "Sweat" the onions without browning. Add the peppers. Let them cook without browning (the peppers remain green). Add the tomatoes, peeled and crushed garlic cloves, sugar, Espelette pepper and diced ham. Let simmer over low heat without a lid, until the water from the tomatoes has evaporated. Adjust the seasoning.
The dough:
Let the piperade cool. Preheat the oven to 240°C (th.8). Flour the work surface. Roll out the puff pastry to about 2mm thickness. Cut out 4 circles 12 cm in diameter. Prick them with a fork. Arrange them on a lightly buttered baking sheet.
Finish:
Spread the piperade on the pastry bases in a layer about 1/2 cm thick. Slip into the oven. Let cook for 10 minutes. Meanwhile, divide the piece of tuna belly in two. Remove the skin with a sharp knife. Cut the flesh into thin strips 2 mm thick.
Remove the pies from the oven. Arrange the tuna slices on the piperade. Drizzle with olive oil. Sprinkle with fleur de sel. Sprinkle lightly with Espelette pepper. Slip into the oven. Cook for 2 to 3 minutes (the tuna should be pink).
Before serving, add a little vinegar. Garnish with chopped chives.