Start the Grits: In a medium pot, bring 4½ cups of water to a boil. Add the kosher salt. Gradually whisk in the stone-ground grits to prevent clumping. Lower the heat and let it simmer gently, stirring often, until the grits are thick and tender, about 35 minutes.
Prepare the Shrimp: While the grits are cooking, peel and devein the shrimp. Keep about one-third of them whole for presentation and chop the remaining into bite-sized pieces. Set aside.
Sauté the Vegetables: In a large sauté pan over medium heat, add a splash of oil or a pat of butter. Once hot, toss in the chopped onions and green bell peppers. Cook until they soften, around 4-5 minutes. Add the minced garlic and cook for another 30 seconds.
Add the Shrimp: Add the chopped and whole shrimp to the pan. Stir well and sauté until they just begin to turn pink and curl, about 2 to 3 minutes. Be careful not to overcook.
Deglaze and Simmer: Pour in the chicken stock and bring the mixture to a simmer. Let it bubble gently for about 5 minutes so the sauce reduces slightly and captures all the savory notes from the pan.
Finish the Grits: Once the grits are creamy and fully cooked, turn off the heat and stir in the shredded white cheddar cheese and unsalted butter until melted and smooth. Taste and adjust the salt if needed.
Final Touches: To the shrimp mixture, add chopped green onions, parsley, and a squeeze of fresh lemon juice. Stir to combine.
Plate and Serve: Spoon a generous helping of grits into shallow bowls. Top with the shrimp and vegetable mixture. Ensure each serving includes at least one whole shrimp for visual appeal. Serve immediately.