Rondon is a rich, delicious traditional Jamaican party dish and is very popular on the Caribbean coast of Costa Rica . The name is the Patois pronunciation of “run down”. “The vast variety of fishes, small game, and wild and domestic meats available to the coast people, in combination with the foods they cultivated on their land, kept them well fed, to say the least. Preparing a meal rarely entailed a trip to the shop. It was merely a matter of “running down” the ingredients in the bush, in the sea, or on the farm. The thrifty housewife put everything together in one pot, simmered it in coconut milk, and called it “rundown” for everything she was able to “run down” that day. If it included fish, yam, plantain, scallions, palmito and Panamanian pepper, it could hardly be better.”
“What Happen” - A Folk History of Costa Rica’s Talamanca Coast —by Paula Palmer, 2005, p 61.
Soak the mackerel in a pot of water overnight to remove most of the salt. If the mackerel is still very salty, boil in water for 20 minutes. Drain mackerel and cut into small pieces. Boil the coconut milk and water in a heavy frying until it looks like curdled custard and oil. Add the mackerel, cover and cook for 12 minutes on medium heat. Stir in the onion, garlic, scallion, tomatoes, Panamenian pepper and thyme. Lower the heat and simmer for 10 more minutes.
Note: You can also use another kind of fish if you don’t have mackerel.