one I originally found as my starting point. Without the sardines. And I changed up the quantities. I was quadrupling the recipe but I still only used 1/4 C raisins and 1/4 C nuts. You can adjust to your tastes. I discovered that there was too much oil for me so I cut that way back. The end result is sweet caramelized onions that have the tang of vinegar with some raisins and pine nuts. And the longer they sit in your fridge, the better they taste. My problem is letting them sit at all. They are good all by themselves or with any kind of fish. Today I had them with baked salmon. I've also had them with sautéed tilapia. I'm sure you can find other things to serve them with.
Before cooking the onions, soak about 1/4 C raisins in 1/2 C white wine. And toast about 1/4 C of pine nuts.