Onion Calzone

Method

1. Clean the spring onions, removing the outer layer and green tops. Cut them into wedges (not rounds).
2. Place the onion wedges in a cold pan with a generous drizzle of olive oil, coarse salt, and a pinch of chili pepper. Cover and stew over low heat, starting from cold, until they soften and release their water.
3. Meanwhile, prepare the dough: on a work surface, mix 00 flour and type 1 flour with salt. Add a good amount of extra virgin olive oil and white wine. Knead with your fingertips to dissolve the salt, then incorporate the flour into the liquids. Continue kneading for 5–10 minutes until you get a smooth but still rustic dough. Reserve a little white wine for later.
4. Wrap the dough in plastic and refrigerate for at least 30 minutes to relax.
5. After the onions have cooked down and lost most of their volume, add the reserved white wine, black olives, 7–8 anchovies, two tablespoons of tomato sauce (or chopped cherry tomatoes), and optionally some raisins that were soaked in white wine. Stir well and continue cooking uncovered until the filling becomes a thick, dry cream (about 1 hour total).
6. Preheat the oven to high heat (around 200–220°C).
7. Take the dough and divide it into two parts—one for the base and one for the lid. Roll out each part very thin (about 2 mm thick) with a rolling pin, using a little extra flour if needed.
8. Oil a baking dish (tiella) and sprinkle with polenta flour. Prick the base dough with a fork.
9. Spread the onion filling evenly over the base, about two fingers thick.
10. Cover with the second rolled-out dough, pressing the edges to seal. Fold the edges toward the center, then prick the lid with a fork.
11. Brush the top generously with olive oil, sprinkle with polenta flour and sea salt flakes.
12. Bake first on the bottom rack for 15 minutes, then move to the middle rack and continue baking until golden and crisp on both sides, about 20–25 more minutes.
13. Let the calzone cool for about 30 minutes before cutting and serving.