Begin by cooking the elbow macaroni according to package instructions in a large pot of salted boiling water. Drain and set aside.
In the same pot, melt the butter over medium heat. Once melted, whisk in the flour to create a roux. Cook for about 2 minutes or until the mixture turns a light golden color.
Gradually add the milk while whisking continuously to ensure there are no lumps. Continue to cook, stirring frequently until the mixture thickens, about 5-7 minutes.
Stir in the garlic powder, onion powder, paprika, salt, and pepper. Lower the heat, and add both the cheddar and Parmesan cheeses, stirring until melted and smooth.
Add the cooked macaroni and shrimp to the cheese sauce, mixing until well combined.
If desired, pour the mac and cheese mixture into a baking dish. Sprinkle bread crumbs on top for added texture.
Preheat your oven to 350°F (175°C) and bake for about 15 minutes, or until the top is golden and bubbly.
Remove from the oven and let it cool for a few minutes. Garnish with fresh parsley before serving.