Slice the onions, toss with the sea salt and let set for a couple of minutes. Add the onions and vegetable oil to a wide 2-quart pot over medium heat and cover. Cook the onions for 10 minutes. (This will help leach the water out of the onions, which will eventually help them caramelize.) When the onions have lost their liquid, lower heat and continue to cook, uncovered, until they become a deep brown, about 35 minutes. If the onions start to stick, add a little water to the pot.
When the onions are nicely browned, pull off heat and let cool for a few minutes. Purée the onions in a blender while still warm, but not hot, adding up to 2 tablespoons water if mixture is too thick. While onions are puréeing, add softened butter little by little.
Mix the sour cream and curry powder and season to taste with salt and pepper.
In small casserole (preferably glass) add the layer of onion purée and chill until the mixture sets. Next add the drained raisins, then top with sour cream. Garnish with chives.
Nutrition information per 2 tablespoons:
Calories82Fat6 gSodium36 mg