In a medium saucepan, bring 4 cups of water or chicken broth to a boil. Add the grits and a pinch of salt. Reduce the heat to low, stir well, and cover. Cook for about 20-25 minutes, stirring occasionally until the grits are thick and creamy.
Once the grits are creamy, stir in the shredded cheddar cheese, and 2 tablespoons of butter until melted and well-combined. Remove from heat and set aside.
In a large skillet, heat 2 tablespoons of olive oil and 2 tablespoons of butter over medium heat. Add the chopped onion and bell pepper, sautéing until tender, about 4-5 minutes.
Add the minced garlic and sauté for an additional minute until fragrant.
Sprinkle in the Cajun seasoning and stir to coat the vegetables evenly.
Add the shrimp to the skillet, cooking until they turn pink and opaque, about 3-4 minutes. Be careful not to overcook. Season with salt and pepper to taste.
To assemble the bowls, spoon a generous portion of the cheesy grits into each bowl and top with the spicy Cajun shrimp mixture.
Garnish with chopped green onions and fresh parsley.