First, bring 4 cups of water to a boil in a large pot. Add ¼ teaspoon of kosher salt. Gradually stir in the grits, reducing the heat to low. You’ll want to whisk the grits gently to avoid clumps. Monitor them and stir occasionally, cooking for about 20 minutes until thickened. Remove from heat.
Once the grits are cooked, add 2 tablespoons of unsalted butter, 2 cups of aged Gruyère cheese, and 1 tablespoon of heavy cream. Stir until everything is melted and thoroughly combined. Season with salt to taste. Cover and set aside.
In a large skillet, melt 2 tablespoons of butter over medium heat. Add the sliced onion and sauté for about 2 minutes until translucent. Toss in the garlic and bell pepper, cooking for another 3 minutes until fragrant.
Season the shrimp with Creole seasoning and cayenne pepper if using. Add the shrimp to the skillet, cooking until they turn pink, about 3-4 minutes.
Stir in the tomato paste, lemon juice, shrimp broth, and Worcestershire sauce. Allow it to simmer for 3-5 minutes, letting the flavors meld together. Add the chopped green onions right before serving.
Place a generous spoonful of grits on each plate and top with the shrimp mixture. Feel free to garnish with extra green onions or a sprinkle of smoked paprika for an extra kick.