In a large pan melt butter, and then add carrots, celery, onion, red bell pepper, and mushrooms. Cook over medium heat until tender.
In another pan cook the diced potatoes in 1 1/2 cups chicken broth until tender. Then drain.
Add the cooked potatoes to the cooked vegetable mixture. Stir in the 1/4 cup flour and coat all veggies.
Then stir in 3 cups chicken broth, half and half. Cook over medium heat stirring until slightly thickened. Reduce heat and add in 3/4 cup of bacon bits, dry mustard, hot sauce, garlic salt, and salt & pepper.
Then gradually stir in cheese stirring until melted. To avoid curdling, don't let the soup boil after the cheese has been added.