1. In a heavy 10- to 12-inch skillet, heat ¼ cup of the olive oil until a light haze forms above it. Add ½ cup of the chopped onions and ½ cup of the chopped green peppers and cook over moderate heat, stirring, for 4 or 5 minutes, or until the vegetables are soft.
2. Stir in 1½ cups of the chopped tomatoes and the yuca, reduce the heat to low, cover and simmer for 30 minutes. Pour in 3 cups of the coconut milk, stir thoroughly, cover, and simmer as slowly as possible for 1 hour, stirring occasionally and mashing the yuca from time to time with the back of the spoon until the mixture becomes a coarse puree. Set aside.
3. In another 10- to 12-inch skillet heat the remaining ¼ cup of oil over moderate heat. Add the remaining ½ cup of onions and ½ cup of green peppers, and cook for about 5 minutes, or until the vegetables are soft but not brown.
4. Add the shrimp, stir them about in the vegetables for 2 minutes, until they turn pink, then stir in the remaining 1½ cups of tomatoes and the remaining cup of coconut milk.
5. Cover the pan and simmer slowly for about 10 minutes before adding the reserved yuca mixture, the dende oil, salt and pepper. Simmer, uncovered, for 2 or 3 minutes to heat the ingredients through, stir in the coriander, and taste for seasoning.
6. Serve at once accompanied, if you like, by pirao de arroz.
