Add bacon to a pan and cook until browned and crispy. Remove from pan and let cool. Reserve bacon grease.

Add mayo, mustard, salt, pepper, and apple cider vinegar to a small bowl. Stir. Pour in reserved bacon grease and mix well until smooth.

Add cabbage slaw mix, cheddar cheese, and green onion. Toss until well coated.

Sprinkle with extra cheddar cheese, bacon, and green onion if desired.