Combine the 4 cups water, 2 cups whole milk, and 1 tsp kosher salt in a saucepan and bring to a gentle boil over medium-high heat, stirring occasionally to prevent scorching.

Slowly whisk in the 1 ½ cups stone-ground grits not instant in a thin, steady stream to prevent lumps. Reduce heat to low, cover, and cook — stirring vigorously every 5 minutes — until the grits are thick, creamy, and tender, about 25–30 minutes. If they thicken too much, add a splash of water or 2 cups whole milk.

Remove from heat and stir in the 3 tbsp unsalted butter and shredded 1 ½ cups sharp cheddar cheese freshly shredded until fully melted and incorporated. Season with ¼ tsp black pepper freshly ground and taste for 1 tsp kosher salt. Cover and keep warm on the lowest heat setting, stirring occasionally.

Pat the shrimp dry with paper towels — this is key for a good sear. In a mixing bowl, toss the shrimp with 1 tsp kosher salt, ¼ tsp black pepper freshly ground, ½ tsp smoked paprika, and ¼ tsp cayenne pepper (if using) until evenly coated. Set aside.

In a skillet over medium heat, cook the 4 slices thick-cut bacon cut into 1/2-inch pieces pieces until crispy and the fat has rendered, about 5–6 minutes. Use a slotted spoon to transfer the bacon to a paper towel-lined plate, leaving the drippings in the pan.

Add the diced medium yellow onion finely diced, 1 green bell pepper finely diced, and 2 stalks celery finely diced to the bacon drippings. Sauté over medium heat until softened and lightly golden, about 5 minutes. Add the 4 cloves garlic minced and cook for 1 minute more, until fragrant.

Sprinkle the 1 tbsp all-purpose flour over the vegetables and stir to coat. Cook for 1 minute to remove the raw flour taste. Pour in the ½ cup low-sodium chicken broth, 2 tsp Worcestershire sauce, and hot sauce (if using), stirring to combine. Bring to a gentle simmer and cook until slightly thickened, about 2 minutes.

Increase the heat to medium-high. Add the seasoned shrimp to the skillet in a single layer. Cook undisturbed for 1–2 minutes until pink on the bottom, then flip and cook for 1 minute more — just until opaque and cooked through. Do not overcook. Remove from heat.

Stir in the 1 tbsp fresh lemon juice and the tablespoon of unsalted butter until the butter melts into the sauce. Taste and adjust seasoning. Fold the reserved crispy 4 slices thick-cut bacon cut into 1/2-inch pieces back in.

Divide the cheesy grits among four warmed bowls. Spoon the shrimp and sauce generously over the top. Garnish with sliced stalks scallions thinly sliced and 2 tbsp fresh parsley roughly chopped. Serve immediately.