In a saucepan, combine flour, salt, black pepper, and cayenne pepper. Gradually whisk in chicken broth and skim milk until smooth.

Cook over medium heat while stirring until it thickens into a sauce. Remove from heat and stir in the prepared mustard and lemon juice.

Meanwhile, prepare the pasta according to the package directions. Once cooked, drain and set aside.

In a skillet, heat olive oil and margarine over medium heat. Add chicken breast slices and cook until fully cooked and slightly browned. Remove and set aside.

Combine the pasta, cooked chicken, and sauce together in a large mixing bowl. Stir well to coat the pasta and chicken with the sauce.