In a large pot, over medium-high heat, cook bacon until crisp.
Remove bacon, with a slotted spoon, to a paper-towel-lined plate; set aside.
Pour off all but 2 tbsp. drippings.
Add onion, celery, and garlic to drippings, in pot, and sweat over medium heat until onion is softened, about 5 minutes.
Stir in flour and cook 1–2 minutes.
Add potatoes, dry mustard, and paprika; cook, stirring to coat potatoes, 1 minute.
Stir in broth, Worcestershire, and Tabasco.
Bring to a boil, reduce heat to medium-low, and cook, partially covered, until potatoes are soft, 10 – 15 minutes.
Use a potato masher to coarsely mash potatoes.
Stir in cheddar and half-and-half until cheese is melted, 2 minutes.
Remove soup from heat; season with salt, black pepper, and cayenne.
Top servings with bacon, scallions and cheddar cheese.
