In a second pot melt the remaining butter and whisk in flour-it will be like a paste. Add the milk slowly and whisk vigorously so that there are no clumps. When combined, bring to an almost simmer (about 3 minutes) and then add the cheese in handfuls whisking in between so that it becomes a creamy mixture. Add the mustard and Worcestershire sauce, then add the carrot mixture to the cheese and stir to combine, allow to cook for 2 minutes together, then it is ready to enjoy! If you like a thicker soup, you can add a few more tablespoons of flour.