Start by heating a medium sized pan over medium heat. Once heated, add the light margarine and swirl around the pan until melted.
Pour in the broth and stir everything together. Slowly sprinkle in the flour while whisking vigorously to get any clumps out. Sprinkle on the seasonings and mix to combine.
Bring the mixture to a slight simmer, then add in the cream cheese. Whisk together as the cream cheese melts then bring the mixture to a slight simmer. Simmer for about 2 minutes, until your desired thickness is reached.