Pat the pork shoulder dry and season all sides evenly with the salt, black pepper, and paprika.
In a mixing bowl, stir together the peach preserves, bourbon, soy sauce, and minced garlic until smooth.
Scatter the sliced onion across the bottom of the slow cooker. Place the seasoned pork on top of the onion.
Pour the peach bourbon mixture over the pork, making sure it covers the top and sides as much as possible.
Cover and cook on low for 8 hours, until the pork is very tender and pulls apart easily with a fork.
Remove the pork to a cutting board and shred or slice it. Spoon some of the cooking liquid and onions over the meat before serving.