Stir together the ground sage, garlic powder and onion powder in a small bowl. Season with salt and black pepper, to taste.
Put the pork tenderloin into a slow cooker. Season it all over with the spice mixture.
Cover and cook on low heat for 6 to 8 hours.
Before the last hour of cooking time, put the glaze ingredients into a saucepot. Bring to a simmer and cook until thickened, about 4 minutes.
During the last hour of cooking time, baste the pork occasionally with the glaze.
Cook until the pork is fork-tender.
Use a knife or two forks to pull the pork into pieces.
Drizzle with more of the glaze.
You can serve now or do this optional step to crisp up the pork: Put the pork onto a aluminum foil-lined baking sheet. Pop the meat under the broiler for a few minutes to crisp it up. Do not walk away! It will burn quickly.
Serve the pork with your desired side dishes.
