1. Heat the oil in a Dutch oven or large heavy pan over medium heat. Add the onions and cook until soft, about 5 minutes. Add the ginger, dried shrimp, garlic and habaneros and cook, stirring, about 2 minutes. Add the tomatoes and cook until they soften and start to break down, about 4 minutes. Add the collards, chicken broth, salt and black pepper. When the broth comes to a boil, cover the pan, lower the heat and simmer until the collards are completely tender, about 30 minutes. Stir in the tamarind and season with additional salt and pepper.
2. Serve with a generous portion of steamed rice.