1. Melt the butter in a medium pan over medium high heat. 2. Add the flour to the melted butter and mix them together, forming a slurry. 3. Pour the milk and vegetable broth into the pot, whisking vigorously until the butter/flour mixture is dissolved. 4. Allow the mixture to boil while you dice the potatoes. 5. Add the potatoes to the soup and allow it to cook for 10 to 15 minutes. 6. Season the soup with salt and pepper and add the cheese. 7. Mix the soup well until the cheese is melted in.