1 lg. onion, diced
1/2 c. butter (1 stick)
6 tbsp. flour
4 c. evaporated skimmed milk
1 c. grated Parmesan cheese
1 tsp. nutmeg
1/4 tsp. cayenne pepper
1 tsp. salt
1 lb. cooked, peeled shrimp (if using frozen shrimp, thaw & drain thoroughly)

Over double boiler, saute onion in butter. Stir in flour. Slowly add milk, stirring constantly until medium white sauce forms. Add Parmesan cheese, nutmeg, cayenne and salt. (Texans may add an additional 1/4 teaspoon cayenne.) Add shrimp, stirring frequently until heated through. Serve over rice or Chinese noodles. Sauce may be prepared ahead and reheated.