To prepare a south of the border shrimp and grits recipe, first you need to prepare the shrimp. First, you'll need: 1 pound shrimp, 2 tablespoons butter, 1 teaspoon kosher salt, and 1 tablespoon melted butter. You can buy shrimp at most grocery stores, or you can make your own at home. If you don't have time to cook shrimp yourself, skip this step and use rotisserie shrimp instead. Heat the butter and butter over medium-high heat. Add the garlic and saute until fragrant, about 1 minute. Stir in the flour and cook, whisking constantly, until the mixture thickens, 3 to 5 minutes. Gradually add the milk and whisk until it's completely incorporated. Remove the pan from the heat and stir in 1 cup shredded cheddar cheese. Serve with guacamole or sour cream.