In a bowl, combine the
tomato paste, beef stock, Worcestershire sauce, chili powder, cumin, cayenne and salt;
mix with a wire whisk.
3
Once beef is fully cooked, 10-12 minutes, pour the mixture over
the beef and stir until well combined. Reduce heat to low and cover. Simmer 10
minutes. Warm the buns in a toaster oven if desired. To serve, spoon hefty amounts onto
the buns.