Whisk raw beef into cold broth in a 7-quart crockpot, breaking meat into very fine bits.

Stir in onion, garlic, tomato sauce, chili powder, paprika, cumin, Worcestershire, and salt.

Cover; cook on low 6 hours, stirring after 2 hours and again after 4 hours to keep texture even.

Confirm beef reaches 160°F; skim surface fat and stir in mustard.

Cook uncovered on high 30 minutes until a spoon leaves a trail for 2 seconds. Switch to warm.