Preheat the oven to 375°F.
Lightly spray a 9x9-inch casserole dish with baking spray and set it aside.
In a medium saucepan, melt the unsalted butter over medium heat.
Add the finely diced bell pepper, onion, and celery.
Cook for 4 to 5 minutes, stirring occasionally, until the vegetables are slightly softened and lightly golden in spots.
Turn off the heat.
Add the cubed cream cheese, mayonnaise, 1 cup of shredded cheddar cheese, and grated parmesan cheese to the saucepan.
Using a rubber spatula, stir the mixture until the cream cheese begins to soften and the ingredients are well combined.
Add the Creole seasoning, hot sauce, black pepper, and garlic powder.
Stir until the seasonings are evenly incorporated.
Gently fold in the cooked, chopped shrimp.
Transfer the mixture to the prepared casserole dish.
Spread it into an even layer.
Sprinkle the remaining 1 cup of shredded cheddar cheese evenly over the top.
Bake for 30 minutes, or until the dip is hot, bubbling around the edges, and lightly golden on top.
Remove the casserole dish from the oven.
Allow the dip to rest for several minutes before serving.
Garnish with chopped parsley.
Serve warm with crackers, chips, toasted bread, or the preferred dipping option.