Put a pan of water on to boil with the onions in it. When the water comes to the boil, turn down the heat and simmer for 25 minutes. Turn off the heat, and leave the onions to cool in the water.
Make the breadcrumbs, and mix most of them with the milk, reserving
When the onions are cool, peel off the outer layer of skin. Trim the root end very carefully, just enough to make it presentable, and to form a small flat base. Trim the top of the onion and discard. Now the fun bit: cut the top quarters off the onions and set aside, then carefully make four onion bowls by removing the centres. The bowl walls need to be two layers thick. Arrange the onion cups in a lightly oiled roasting dish with a few tbsp of water in the base.
Chop the onion centres and caps finely. In a frying pan heat a tbsp or so of olive oil and sauté the onion pieces until golden brown over a very high heat. Put in a food processor along with the milk-soaked breadcrumbs, the parsley, tuna, chilli, capers, anchovies, garlic and oregano. Process until a coarse paste, then taste and adjust seasoning, but as it contains anchovies and chilli, it should need neither salt nor pepper.
Spoon this mixture into the onions, heaping it up. Sprinkle the tops with the reserved dry crumbs and moisten with a little oil.
© 1996 Alastair Little. All rights reserved.