Add the pork, salt, pepper, garlic powder, cumin and paprika to a 6-quart slow cooker. Toss to combine, then pour in the apple juice. Cover with the lid and let cook for 8 hours on low, or until the pork is easily shreddable.
Remove the pork from the juices to a serving dish and shred with forks or fingers.
Add the butter to a small skillet over medium heat and let melt. Whisk in the flour until combined, about 1 minute. Add 1 cup drippings from the slow cooker and whisk until thickened. Taste for seasoning. Drizzle over the pork or transfer to a serving dish. Serve the pork warm with warm gravy and a sprinkle of chopped parsley. Eat with the dinner rolls.