These scalloped potatoes turn out unbelievably creamy, and the secret is in the sauce!A proper scalloped potato dish needs layers that hold their shape while still being rich and tender.The key is slicing the potatoes as evenly as possible—use a mandoline if you can, but a sharp knife and steady hand work too.The browned, bubbling top with crispy edges gives the right contrast to the soft, velvety layers underneath.A pinch of nutmeg in the sauce brings out the depth of the cheese without overpowering the dish!