Bring 3 cups of water to a rolling boil in a medium saucepan over high heat. Once boiling, uncover and gradually whisk in the grits to prevent clumping. Season with 1 teaspoon of salt and ½ teaspoon of freshly ground black pepper. Reduce the heat to medium-low and cook, stirring occasionally, until the mixture thickens and the grits become smooth and creamy, about 5 minutes. Stir in the Parmesan cheese and 1 tablespoon of butter until melted and fully incorporated. Taste and adjust the seasoning as needed with salt and pepper, then cover the pan to keep the grits warm while preparing the shrimp.

Pat the shrimp dry with paper towels and season generously with salt and black pepper. In a large skillet, melt the remaining 2 tablespoons of butter over medium-high heat. Add the shrimp, minced garlic, and a pinch of cayenne pepper if desired. Cook for 3 to 4 minutes, tossing occasionally, until the shrimp turn pink and opaque. Be careful not to overcook them — they should remain tender and juicy.

Remove the skillet from the heat and stir in 2 tablespoons of water along with the lemon juice and chopped parsley. Toss well to coat the shrimp evenly in the buttery garlic sauce. Taste and adjust seasoning with a touch more salt or pepper if necessary.

Spoon the warm, cheesy grits into shallow serving bowls. Arrange the shrimp on top and drizzle over the lemon-garlic sauce from the pan. Garnish with fresh parsley and serve immediately with lemon wedges on the side for an extra burst of brightness.