Cebollas Rellenas (Spanish Stuffed Onions)

Bring a large pot of salted water to a boil. Trim the root end of each onion just enough to sit flat, then cut a thin slice off the top. Carefully remove the central core of each onion with a small knife and spoon, leaving a shell about 1 cm (1/2 inch) thick. Reserve the removed onion flesh and set the shells aside.

Lower the onion shells into the boiling water and blanch for 5 minutes to soften slightly. Lift them out with a slotted spoon and drain upside down on a plate. This step helps them hold their shape and reduces harshness.

Heat 2 tbsp olive oil in a wide skillet over medium heat. Add the reserved chopped onion flesh and cook for 5 minutes until soft. Add the garlic and chorizo, if using, and cook for 1 minute. Add the ground pork, breaking it up with a spoon, and cook until no longer pink, about 5 minutes. Stir in the rice, grated tomato, smoked paprika, oregano, salt, and pepper, and cook for 1 minute. Pour in the white wine and simmer until almost evaporated. Add 120 ml (1/2 cup) of the stock, bring to a simmer, then cover and cook for 8 minutes until the rice is just tender but still a little firm. Remove from the heat and stir in half the parsley. Let cool slightly.

Preheat the oven to 190°C (375°F). Place the onion shells in a baking dish just large enough to hold them snugly. Spoon the filling into each shell, mounding it slightly and pressing gently. Pour the remaining stock around the base of the onions. Cover the dish tightly with foil and bake for 25 minutes.

Remove the foil. Mix the breadcrumbs with the remaining 1 tbsp olive oil and scatter over the tops of the onions. Return to the oven and bake uncovered for 15–20 minutes, until the tops are golden and the onions are completely tender when pierced with a knife. If the dish looks dry, add a splash more stock.

Let the onions rest for 5 minutes. Scatter with the remaining parsley and serve warm, spooning some of the pan juices over each onion.