This easy SLOW COOKER STUFFING Recipe. Step-by-Step. is perfect for busy families. Comes together quickly with a few staple ingredients! INGREDIENTS1 cup butter 2 cups chopped celery 1 cup chopped onion 1 teaspoon poultry seasoning 1 1?2 teaspoons sage leaves, crumbled 1?2 teaspoon pepper 1 1?2 teaspoons salt...