In a second sauce pan heat butter and flour and cook for 2 minutes or until the roux is a blonde color. Add warm milk and whisk until combined. Cook the sauce for 5 minutes or until thickened then season with salt and pepper.
Add cheese and whisk until melted then set aside.
In a skillet, brown meat until cooked through and season with salt and pepper then add to the cheese sauce. Stir chopped mushrooms and cook 3 more minutes.
Cook pasta according to package directions, drain and combine with sauce and meat mixture.
