Shred the green cabbage into thin 1/8-inch strips using a sharp knife or mandoline, then grate the carrots using the large holes of a box grater, and thinly slice the red onion. Transfer all prepared vegetables to a large mixing bowl. I find that shredding the cabbage right before dressing it helps maintain its crisp texture—pre-shredded cabbage can become watery and lose its satisfying crunch.

In a separate small bowl, whisk together the apple cider vinegar, Dijon mustard, honey, and extra-virgin olive oil until emulsified. Add the celery seed, sea salt, freshly cracked black pepper, and red pepper flakes, then whisk once more to combine all flavors evenly. The mustard acts as an emulsifier to help the oil and vinegar blend together smoothly, creating a more cohesive dressing.

Pour the vinaigrette from Step 2 over the prepared vegetables in the bowl and toss vigorously for about 2 minutes to evenly coat everything and begin releasing the vegetables' natural juices. Fold in the fresh chopped parsley just before serving to preserve its bright color and fresh flavor. I like to let the coleslaw sit for 5-10 minutes before serving—this allows the flavors to meld while the vegetables remain pleasantly crisp.