Seashells Alfredo

1/4 C chopped scallion
2 cloves garlic, minced
1 T flour
1 can (12 oz) evaporated skim milk
1/4 C freshly grated Parmesan cheese
1/4 C freshly grated Romano cheese
1/2 tsp dried parsley
1/2 tsp dried thyme
1/2 tsp dried basil
1/4 C finely chopped red bell pepper
6 C hot cooked macaroni shells

Sauté scallion and garlic for 2 minutes. Stir in flour and cook briefly. Gradually stir in milk and bring to a boil, stirring constantly. Cook over medium-low heat until thick, about 3 minutes. Remove from heat and stir in cheeses, herbs, and red pepper. Serve immediately over macaroni shells.