In a medium serving bowl, combine the prepared purple and green cabbage, carrots and parsley. Set aside.
Measure out your seeds into a small skillet. Toast over medium heat, stirring frequently, until the seeds are fragrant and the pumpkin seeds start to make little popping noises. Pour the toasted seeds into the mixing bowl and toss to combine.
To make the dressing, in a small bowl, combine the olive oil with 2 tablespoons lemon juice. Add the garlic, cumin and salt and whisk until thoroughly blended.
Drizzle the dressing over the slaw and toss until all of the ingredients are lightly coated in dressing. Taste and add an additional tablespoon of lemon juice if the slaw needs a little more zip. Serve immediately or cover and refrigerate to marinate for up to several hours.
Adapted from Cookie and Kate