Heat the oil in a large skillet on medium-high heat. Add the kielbasa and cook for 7 minutes, or until browned, stirring occasionally.
Reduce the heat and remove the kielbasa from the pan. Set aside.
Add the butter and onion to the pan. Cook for 2 minutes, stirring occasionally.
Add the cabbage to the pan and cook uncovered for 10 minutes, or until the cabbage is cooked, stirring fairly often.
Stir in the paprika. Return the sausage to the skillet and cook for 1 minutes, or until the sausage is heated through. Season with salt and pepper if using.