For the grits:
4 cups water
1/2 teaspoon salt
1 cup regular grits
6 ounces sharp Cheddar cheese, grated
3 tablespoons butter
For the shrimp:
1 pound fresh medium shrimp
2 cups water
4 tablespoons butter
1 large onion, chopped
1/2 green bell pepper, seeded and chopped
2 garlic cloves, minced
1 cup diced ripe fresh tomatoes
1/2 teaspoon dried thyme, crumbled
1 tablespoon all-purpose flour
1 tablespoon tomato paste
1/2 cup heavy cream
2 teaspoons Worcestershire sauce
Salt and freshly ground black pepper, to taste
Tabasco sauce, to taste
2 tablespoons chopped fresh parsley leaves
Combine the water and salt in a heavy saucepan and bring to a boil.
Gradually add the grits, stirring, reduce the heat to low, cover, and cook till the liquid has been absorbed, 15 to 25 minutes, stirring occasionally.
Remove the pan from the heat; add the cheese and butter, and stir till melted. Keep warm.
Peel and devein the shrimp, combine the shells and water in a saucepan, and reserve the shrimp. Bring the water to a boil, reduce the heat slightly, cook till the liquid is reduced by half, and strain the stock into a bowl.
In a large skillet, melt the butter over moderate heat, add the onion, bell pepper, and garlic and cook, stirring, till softened, about 3 minutes. Add the tomatoes and thyme and cook about 3 minutes longer. Sprinkle the flour over the top and stir well. Add the reserved shrimp and cook, stirring, till they turn pink, about 2 minutes.
Add 1/2 cup of the stock, cook 3 minutes longer, add the tomato paste, and stir well. Add the cream, Worcestershire, salt and pepper, Tabasco, and, if necessary, a little more stock to make a sauce that easily coats the shrimp. Heat well.
To serve, spoon a mound of grits in the center of each serving plate, spoon shrimp around the grits, and sprinkle parsley over the top.