Bring water, salt, and 1 tablespoon butter to a boil in a 3-quart heavy saucepan. Whisk in grits and cook at a bare simmer, covered, stirring frequently, until grits are tender and thick, about 1 hour. Stir in cream and remaining tablespoon butter and remove from heat. Make topping 15 minutes before grits are done:
Cook chorizo and ham in 1/2 tablespoon butter in a 12-inch heavy skillet over moderate heat, stirring, until ham is golden, about 3 minutes. Transfer chorizo and ham to a plate with a slotted spoon. Add 1/2 tablespoon butter to skillet and heat until foam subsides. Cook scallops until golden on both sides and just cooked through, about 2 minutes.
Transfer scallops to a plate with a slotted spoon. Add another 1/2 tablespoon butter to skillet and cook shrimp, turning, until just cooked through, about 3 minutes. Stir in chorizo, ham, scallops, remaining 1/2 tablespoon butter and remaining ingredients. Cook, stirring and scraping up any brown bits in skillet, until heated through, then season with salt and pepper.
Serve Topping over grits.
Makes: 4