Prepare the tenderloins by trimming off excess fat and the
silver skin (the tough part that may cover some of each tenderloin).
Pour the beef broth into your slow cooker.
Add the spice rub ingredients (brown sugar, smoked paprika,
garlic powder, onion powder, chili powder, Italian seasoning, salt &
pepper) to a small bowl and stir together. Using your hands, coat the
tenderloins all over with the spice rub. You may want to do this on a plate
with each tenderloin one at a time.
Add the pork tenderloins to your slow cooker, along with any
excess rub that is on the plate. Place the butter pats on and around the
tenderloins and close the lid.
Cook on low for 4 hours and check for doneness (150
degrees). Cook on low until you reach
this temperature.
Remove to cutting board and let rest for 15 minutes before
slicing.