1 med.onion, finely chopped
2 sm. garlic cloves, minced
1/4 c. dry white wine or dry sherry
1 tbsp butter
1-1/2 tbsps cornstarch
2-3/4 c. lo-fat milk
1/4 c. grated Parmesan cheese
1/2 c. grated nonfat Parmesan cheese topping (2 ounces)
1/2 c. nonfat sour cream
1/4 c. chopped fresh chives
1 tsp Worcestershire sauce
1/2 tsp Dijon mustard
1/8 tsp white pepper
Salt, to taste
12 ounces non-egg fettuccine noodles cooked according to package

In a 12-inch nonstick skillet, combine onions, garlic, wine, and butter. Cook over medium heat, stirring frequently, 6 to 8 minutes or until onions are tender. If liquid begins to evaporate, add a bit of water. In a cup, combine cornstarch with 1/4 cup milk; stir to mix well. Stir remaining 2-1/2 cups milk into skillet. Bring liquid in pan to a boil over medium-high heat. Stir in cornstarch mixture, stirring until mixture thickens. Boil 1 minute, stirring. Reduce heat so that sauce does not boil. Stir in Parmesan cheeses. Stir in sour cream, mixing well and whisking if necessary to smooth. Stir in 1/4 cup chives, Worcestershire sauce, mustard, and pepper, and stir well. Add salt, cook over very low heat an additional 2 to 3 minutes until flavors are well blended. Arrange fettuccine on a serving platter. Top with sauce.