Mix the chili powder, brown sugar, garlic powder, salt and cumin in a small bowl. Rub mixture over the pork roast, creating a thick crust.
Place onions in bottom of crockpot and lay pork butt on top. Pour beef broth along side the pork butt, being careful not to pour directly overtop of the pork butt.
Cover and cook on the low setting for 10-12 hours. Meat should just about be falling apart.
Remove meat, shred and discard the fat.
Serve as desired.
Notes
My preference is to shred the meat and leave it plain and allow everyone to doctor their own.
Serve atop a big bowl of mac and cheese
Serve with any of your favorite BBQ sauces
Serve with the jus from the roast
If making sandwiches, consider topping with coleslaw.