Preheat oven to 400˚F.
Rinse the quinoa with cold water in a fine-mesh sieve. Transfer to a medium pot and cover with 1 1/3 cup water. Bring to a boil, then turn heat down to a simmer, cover, and cook until liquid has absorbed, about 15-18 minutes. Fluff the quinoa with a fork, transfer to a large bowl, and set aside.
Spread the sweet potatoes out on a rimmed baking sheet and drizzle with a tablespoon of the olive oil. Sprinkle with salt and pepper, and toss gently to coat. Bake in the upper third of oven until golden and tender, 25-30 minutes. Allow to cool at room temperature.
In a small mixing bowl, whisk together the remaining 5 1/2 tbsp of olive oil, apple cider vinegar, mustard, and salt and pepper/
Add the roasted sweet potatoes to the bowl of quinoa. Add the diced apples, baby greens, chopped parsly. and sliced red onion. Drizzle with the dressing, and toss well to coat. Serve immediately.