Apple Cinnamon Slow Cooker Pork Loin: Slice slits into pork loin horizontally, about 3/4 through meat. Fill each slit with an apple slice and drizzle honey over top. Sprinkle with cinnamon. Transfer pork loin to slow cooker. Layer onions over top. Cook on low for 3-4 hours. I added extra apple slices around the pork and a little apple juice.