Friggione (Onion and Tomato Relish)

Steps

1. Heat enough olive oil into a heavy saucepan to cover the bottom (probably about 2 tbsp).
2. Cook the onions in the oil over low heat for at least 1 hour, until they are soft. Stir occasionally to keep them from sticking, and add a little more oil if necessary.
3. While the onions are cooking, blanch the tomatoes in boiling water for about 10 seconds each to loosen the skin. Peel the tomatoes and discard the skin.
4. Roughly chop the tomatoes into a few large pieces.
5. Stir the tomatoes into the onions. Cook for at least another hour, stirring occasionally.