Crisp the bacon: In a skillet over medium-high heat, cook the bacon pieces until crispy and browned. Remove the bacon with a slotted spoon and set aside, leaving the rendered bacon grease in the pan.
Layer the slow cooker: Place the sliced onions and cabbage wedges at the bottom of your slow cooker. Scatter the cooked bacon pieces over and between the cabbage wedges.
Mix the liquid: In a small bowl or measuring cup, whisk together the chicken broth, apple cider vinegar, brown sugar, garlic powder, salt, and black pepper. Pour the mixture evenly over the cabbage and bacon.
Slow cook: Cover and cook on LOW for 5 to 6 hours (or on HIGH for 3 to 4 hours), or until the cabbage is tender and has absorbed all the rich flavors.
Serve: Gently toss or serve warm with the flavorful juices spooned over the top.