• 3 medium blood oranges (If not available, substitute 2 large, juicy navel oranges)
• 2 tbsp olive oil
• 2 cups finely chopped onions
• 1½ tsp fresh ginger, peeled and finely minced
• About 1 tbsp orange blossom or other light floral honey
• Salt and freshly ground black pepper
• 1 pound rhubarb, trimmed, fibrous strings removed with a vegetable peeler
• 1 cup fresh orange juice
• generous pinch of cinnamon
• 2 cups (about 1 pound) canned, peeled plum tomatoes, coarsely chopped, and ½ cup of their liquid 
• Juice of ½ lemon

• 3 pounds fish fillet or steaks (choose salmon or white-fleshed fish like red snapper, grouper, sea bass, halibut, cod, lemon or grey sole)
• If steaming the fish, mild lettuce or cabbage leaves

Garnish: ¹\³-¹\² cup finely minced fresh mint leaves

1. start the sauce. With a vegetable peeler, remove a long strip of zest from one of the oranges. Put it in a small saucepan with water to cover, and bring to a boil. Drain, rinse, and pat it dry. mince the zest fine. Peel 2 of the blood oranges (or 1½ of the naval oranges), removing all of the bitter white pith and any seeds. Slice the oranges into chunks using a serrated knife. Set the orange zest and chunks aside. (You will be using the remaining blood orange, or half navel orange, to garnish the finished dish.)
2. In a 10-inch heavy skillet, warm the oil over moderate heat. Add the onions, and cook, stirring, for 5 minutes until they are shiny and lightly softened. Add the minced orange zest, ginger, and 1 tsp of the honey. Sprinkle lightly with salt and pepper. Continue cooking over low heat, stirring occasionally, until the onions are pale gold and very soft and sweet 15-20 minutes.
3. While the onions are cooking, prepare the rhubarb. Cut it into 1-inch chunks and place it in a medium saucepan. Add ½ cup of the orange juice, the remaining 2 tsp of honey, the cinnamon, and a pinch of salt. Bring the mixture to a boil, then simmer, stirring occasionally, until the rhubarb is very tender, 6-8 minutes.
4. When the onions are ready, add the remaining ½ cup orange juice to the skillet and boil the mixture, stirring and scraping it so it does not burn, for 3-4 minutes, until the liquid evaporates and the onions are deep golden. Stir in the tomatoes and their liquid and cook over moderately high heat until they break up, about 10 minutes. Add the rhubarb mixture to the sauce, and cook over moderate heat for 5 minutes.
5. Add the reserved orange chunks, and simmer for 5-7 minutes, until the sauce is thickened and the flavors well-blended. Season to taste with salt and pepper and some of the lemon juice. Taste again and, if needed, add additional honey or lemon juice until you reach your perfect sweet-and-sour balance. Let the sauce cool to room temperature, then cover and refrigerate it for at least 12 hours or up to three days to blend the flavors.
6. Prepare the fish, either poaching or steaming it. 

To poach the fish: in a deep, lidded skillet or sauté pan large enough to hold the fish in a single layer (If preparing several thin fillets, you will probably need to cook them in batches), bring 3 inches of water and salt and pepper to taste to a boil. Reduce the heat to a bare simmer, lower the fish into the water, and cover the pan. Poach until the fish is just cooked through, 6-12 minutes, depending on the variety and thickness of the fish.

To steam the fish: In a heavy, large, wide pot, like a 5-6-quart Dutch oven, add water to a depth of 1½ to 2 inches. Arrange a rack in the pan that stands at least 1 inch above the water. (If your rack's legs are not high enough, set it over 2 custard cups or empty tuna cans.) Bring the water to a boil. Line the rack with a layer of mild lettuce (iceberg or Boston, for example) or cabbage leaves, then place the fishon top in a single layer (if cooking thin fillets, you will probably have to steam the fish in batches). The leaf "bed" for the fish gentles the steam and prevents the cooked fish from falling through the rack as you try to lift it out. Reduce the heat to medium, cover the pot and steam until the fish is just cooked through, 6-12 minutes, depending on the variety and thickness of the fish.

To test the fish for doneness: Insert a thin-bladed knife in the thickest part. The fish should be opaque or show a slight bit of translucence, according to your preference.

7. Remove the fish to paper toweling or a clean kitchen towel (unscented by detergent) to drain, then, carefully transfer it to a serving platter. Peel off any skin on the fish. You can serve the fish room temperature, chilled (but not icy cold), or warm. If not serving the fish warm, cool it to room temperature, and if desired, cover and chill the fish for at least 12 hours and up to 2 days. Serve the fish room temperature, chilled (but not icy cold), or reheat it gently and serve it warm.

8. Just before serving, blot up any additional liquid exuded by the fish. Cut the remaining blood orange (or half navel orange) into very thin slices. Tuck the slices around the fish and sprinkle lavishly with the chopped mint. Pass a sauceboat with the remaining sauce (heated through, if serving the fish warm).