Soak cashews. Then drain thoroughly and add to a high-speed blender along with water, maple syrup, mustard, white vinegar, apple cider vinegar, onion, and celery salt (or seeds).
Blend on high until creamy and smooth, scraping down sides as needed. If too thick, add more water to thin. If too thin, you can compensate by adding more (raw) cashews (they don't need to be soaked).
Taste and adjust flavor as needed, adding salt and pepper to taste, more celery salt or seeds for more pronounced celery flavor, onion for bite, maple syrup for sweetness, mustard for tanginess, or vinegar for acidity.
Add carrot and cabbage to a mixing bowl and top with dressing. Toss to combine. Enjoy immediately or store covered in the refrigerator to chill - about 4 hours.
*For a nut-free option, you can sub 1 cup store-bought or our vegan mayonnaise per 1 cup cashews. Adjust other flavors to taste (you may need less vinegar and sweetener). *Adapted from Barefeet in the Kitchen.