In a medium bowl, add 6 cups of shredded cabbage (use a mix of green and red/purple cabbage for color and texture).
In a small bowl, whisk together 1/2 cup mayonnaise, 1/2 cup sour cream, 2 tbsp apple cider vinegar, 1/4 tsp Kosher salt, 1/4 tsp black pepper, and 1 tsp seafood seasoning until smooth and creamy.
Pour the dressing over the shredded cabbage.
Use tongs to toss everything together until the cabbage is evenly coated with the dressing.
Taste and adjust seasoning if needed.
For best flavor, let the coleslaw marinate in the refrigerator for a few hours or overnight. Serve chilled.