Cook fettuccine according to package directions. Meanwhile, in large saucepan, saute onion in margerine until tender. stir in flour until blended. gradually stir in cream. bring to a boil over medium heat, stirring constantly. reduce heat to a simmer. stir in ham, 1/2 cup cheese, garlic salt, oregano and nutmeg. drain fettuccine; serve with sauce. sprinkle with remaining cheese.