Heat a large nonstick skillet over medium heat. Once hot, add 1/2 Tablespoon of the oil and swirl to coat the bottom of the pan. Add the sliced kielbasa pieces to the pan and brown. Once the first side has browned, flip and brown the other side (about 3-4 minutes per side). Transfer the kielbasa from the pan to a clean dish.

Add the remaining oil to the pan and swirl to coat the bottom of the pan. Add the sliced onions and cook until almost translucent (about 4 minutes). Add the peeled carrots and garlic and cook until the carrots are softened and the garlic is aromatic (about 2 minutes).

Once the carrots have softened, add in the cabbage and use tongs to toss everything together, making sure the cabbage is coated in the oil. Add in the apple cider vinegar, seasoning salt, and pepper. Mix together to evenly coat the cabbage. Cook the cabbage until it softens and wilts, using tongs to toss it occasionally to ensure even cooking and mix the carrot slices throughout the cabbage (about 15-20 minutes).

Once the cabbage has softened, add the cooked kielbasa back to the cabbage and mix together. Stir to combine and cook for a few minutes, or until the kielbasa is heated through. Serve immediately.