Pat 1 pound peeled deveined shrimp dry with a clean paper towel and season with 1 teaspoon salt and 1 1/2 tablespoons cajun seasoning. Set aside, at room temperature.
Bring water to a boil in a large saucepan over high heat. Reduce heat to low, add grits, and cook, stirring frequently, for 10 to 15 minutes, until water is absorbed. Take a bite—if the grits are still hard, add another splash of water and keep cooking. Stir in the kernels from 2 ears of corn, 1 cup grated Cheddar cheese, 1 teaspoon salt, 1/2 teaspoon garlic powder, and 1/8 teaspoon pepper and cook until cheese is melted. Turn heat off and cover with a lid until ready to serve. If your grits get too thick by the time you’re ready to serve, just stir in a splash of water over low heat!
While the grits are cooking, heat a large skillet over medium-high heat for several minutes. Warm 1 tablespoon olive oil and swirl to coat the pan. Add the marinated shrimp in a single layer and cook for 1 to 2 minutes, until shrimp are opaque and the seasonings start to blacken. Flip and cook for one to two more minutes, until the second side is cooked, then remove skillet from heat and stir in 3 tablespoons butter, the juice of 1 lemon, and 1 tablespoon honey, scraping up any bits that are stuck to the pan. Stir until the shrimp are coated in Cajun honey butter.
Divide the grits between plates or shallow bowls. Top with shrimp and be sure to scrape all of the lemon-butter over the top. Garnish with parsley. Cut the remaining lemon half into wedges and serve alongside.