Step 1

Preheat oven to 350°F. Coat a 3-qt. rectangular baking dish with cooking spray. Cook macaroni according to package directions; drain. Return macaroni to pan.

Step 2

Meanwhile, in a large bowl toss together shredded Swiss and Gruyère cheeses, flour, and garlic. In a large saucepan heat broth and wine over medium just until bubbles form around edge of pan. Add cheese mixture, 1 cup at a time, whisking constantly after each addition until cheese melts. (Mixture may not be completely smooth at this point.) Do not boil. Remove from heat. Stir in shrimp and seafood seasoning.

Step 3

Pour cheese mixture over macaroni; stir gently to combine. Fold in cubed Swiss cheese. Spoon pasta mixture into prepared casserole. Sprinkle crushed crackers evenly over top; dot with butter.

Step 4

Bake, uncovered, 35 to 40 minutes or until bubbly and topping is golden. Sprinkle with green onions.