Slightly modified from source for easier use.
Adapted from themerestaurantsathome.blogspot.com
lb elbow pasta
tablespoons butter, divided
lb medium shrimp, cut in thirds
teaspoon Cajun seasoning, divided
tablespoon grated onion
cup Parmesan cheese, grated
cup Cheddar cheese, grated
cup Monterey jack cheese, grated
salt and pepper
Preheat oven to 350 degrees. 1. Cook pasta according to directions. 2. Melt butter in medium sauce pan. Add shrimp, sprinkle with 1/4 teaspoon Cajun seasoning. Cook 3-4 minutes, remove. 3. In same pan melt 1 tablespoon butter, add onion and saute 1 minute. 4. Whisk in flour, cook 1 minute. 5. Whisk in milk and heat approximately 4 minutes. 6. Add Cheddar and Monterey Jack cheeses, stir until smooth. 7. Add 1/4 teaspoons Cajun seasoning, salt, and pepper. 8. Stir in cooked shrimp and pasta. 9. Pour into buttered casserole dish. 10. Top with Parmesan cheese, bread crumbs, 1 1/2 tablespoons melted butter and parsley. Bake 45 minutes or until browned and bubbling.