Here are quotes of the relevant parts (in case of link rot):
1.Meanwhile, in a large cast-iron or other heavy skillet, melt butter over medium heat. Stir in flour until smooth; gradually whisk in cream. Bring to a boil, stirring constantly. Cook and stir until thickened, about 2 minutes. Reduce heat; stir in cheese until melted.
In a saucepan, melt butter over medium heat. Stir in the flour and salt until smooth. Gradually add milk. Bring to a boil; cook and stir until thickened, about 2 minutes. Stir in cheese. Pour over meat mixture; mix well. Reduce heat; cook, covered, until heated through. If desired, serve with biscuits.
From first and second recipes respectively