Instructions

• Preheat oven to 350°F (175°C). Spray a 9×13-inch baking dish with cooking spray.
• Bring a large pot of salted water to a boil. Cook 1 pound elbow pasta until just al dente according to package directions. Drain, return to the pot, and set the pasta aside.
• In a large skillet over medium-high heat, melt 2 tablespoons butter. Add 1 pound shrimp, sprinkle with 1/2 teaspoon Cajun or Creole seasoning, and cook about 2 minutes per side, slightly undercooking (shrimp will finish cooking in the oven). Remove shrimp from the skillet and set aside.
• In the same skillet over medium heat, add 3 tablespoons butter. When melted, stir in 3 tablespoons all-purpose flour and cook, stirring, for 1 minute to make a roux.
• Gradually whisk in 1 1/2 cups whole milk, then whisk in 1 1/2 cups evaporated milk. Bring the mixture to a simmer and simmer for 2 to 3 minutes, whisking occasionally.
• Add 1 teaspoon Cajun or Creole seasoning, 1/2 teaspoon garlic powder, and 1/4 to 1/2 teaspoon black pepper to the sauce. Reduce heat to low.
• Set aside 1/2 cup shredded sharp cheddar cheese and 1/2 cup shredded Colby Jack (or Monterey Jack) cheese. Add the remaining shredded cheeses to the sauce a handful at a time (use the rest of the 3 cups cheddar and 3 cups Colby Jack), stirring until each addition is fully melted before adding more.
• Stir 1 cup lump crab meat and the cooked shrimp into the cheese sauce.
• Pour the cheese-and-seafood mixture over the cooked pasta in the pot. Stir gently to combine, then transfer the combined pasta and sauce to the prepared 9×13-inch baking dish.
• Sprinkle the reserved 1/2 cup cheddar and 1/2 cup Colby Jack (1 cup total) evenly over the top of the pasta.
• In a small bowl, combine 1 tablespoon melted butter, 1/3 cup Panko crumbs, and 1/3 cup shredded Parmesan cheese. Sprinkle this breadcrumb mixture evenly over the cheese layer.
• Bake in the preheated oven for 20 minutes. If you prefer a more browned top, place under the broiler for 1–3 minutes, watching closely so it does not burn. Remove from oven and let sit a few minutes before serving.