For the shrimp: Add the oil to a large pot and place over medium heat. Once the oil is hot, add the butter to pot and let it melt into the oil. Season the shrimp with the cayenne, salt, and pepper in a medium bowl, then add the shrimp to the pot and sear, stirring occasionally, until cooked through, 2 to 3 minutes. Transfer the shrimp to a medium bowl and set aside.
For the sausage: Add the sausage to the same pot used to cook the shrimp. Cook the sausage over medium heat, stirring often, until the fat has rendered, 5 to 10 minutes. Place a lid slightly askew over the pot and use it to hold in the sausage while pouring the oil into a small dish (once the oil is cool, discard). Stir in the onion, bell pepper, celery, and garlic and cook, stirring constantly, until the onion softens, about 5 minutes. Add the tomatoes and the chicken stock (or water). Cook until the mixture looks stewy and the vegetables are tender, about 30 minutes. Stir the reserved shrimp into the mixture, reduce the heat to low, and cook gently for 8 to 10 minutes (don't let the shrimp become rubbery). Stir in the sour cream.
For the grits: While the sausage cooks, follow the package instructions for making 4 to 6 servings of grits, melting the butter into the boiling water before adding the grits to cook them. Once the grits are cooked, add the pepper and cheese. Stir until the cheese is melted.
Divide the grits among wide, shallow bowls. Spoon the shrimp and sausage mixture over the grits and serve sprinkled with cheese.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Suzanne Jackson, Lagniappe Today, New Orleans, Louisiana