First things first, get your cabbage, carrots, apples, and red onion ready. Thinly shred the green cabbage and carrots using a sharp knife, a box grater, or a food processor with a shredding disc. Core the apples and cut them into thin matchsticks (julienne), then finely mince the red onion.

In a large mixing bowl, combine the mayonnaise, apple cider vinegar, Dijon mustard, granulated sugar, celery seed, kosher salt, and black pepper. Whisk everything together thoroughly until the dressing is smooth and well combined. Give it a quick taste and adjust the sugar, salt, or vinegar if you like it sweeter or tangier.

Add the shredded cabbage, carrots, julienned apples, and minced red onion to the bowl with the dressing. Use a large spoon or your hands (wearing gloves, if preferred) to gently toss everything together until all the vegetables and apples are evenly coated with the dressing.

Cover the bowl with plastic wrap and refrigerate for at least 30 minutes. This chilling time allows the flavors to meld beautifully and the cabbage to soften slightly, giving you the best texture. If you have more time, an hour or two is even better!

Give the coleslaw a final stir before serving. Taste it one last time and add a pinch more salt or pepper if needed. Serve alongside your favorite barbecue, grilled chicken, or sandwiches.