In a small bowl, or measuring cup, whisk together ½ cup mayonnaise, ¼ cup coconut milk, 1 tsp. horseradish sauce, 2 tsp. sugar, and 2 tsp. apple cider vinegar.
In a medium bowl, combine thinly sliced green cabbage with very thinly sliced purple cabbage.
Once the dressing is creamy and smooth, pour it over the prepared cabbage; stir well.
Place in an airtight container, in the refrigerator, until ready to serve.
Just before serving, remove from the refrigerator and give it a quick stir to make sure any dressing at the bottom coats the cabbage.
