8 large raw shrimp (about 15 count), peeled, deveined, cut in half lengthwise
4 cups sliced white button mushrooms
1/2 cup chopped green onions
1/2 cup grated Parmesan cheese
1/2 cup shredded Swiss cheese
Melt butter in 8-inch saucepan. Add flour and mix until smooth. Set aside.
In a 12-inch saucepan, combine milk and chicken base; bring to boil. Pour
hot milk mixture into reserved flour/butter mixture and whisk until smooth.
Cook over medium heat until mixture just starts to bubble, about 5 minutes.
Remove from heat, strain and discard any lumps. Set aside.
Heat oil in a large skillet.
Add scallops and shrimp; cook until almost cooked through.
Add mushrooms and green onions and cook until mushrooms are
just limp and seafood is cooked through.
Drain off excess liquid.
Add reserved sauce and Parmesan cheese and cook, stirring frequently,
for 1 minute or until mixture is heated through.
Divide mixture among 4 individual 2-cup casseroles or one 8- to 10-cup casserole.
Top with Swiss cheese and broil until lightly browned, 1 to 2 minutes.