Preheat and prep. Preheat your oven to 400°F and line two large baking sheets with parchment paper. Dice the carrots, squashes, and sweet potato into bite-sized pieces, keeping them roughly the same size for even roasting.
Season and roast the vegetables. Add the vegetables to the baking sheets. Drizzle with olive oil, sprinkle with kosher salt, cinnamon, and garlic, then toss to coat. Roast for 35–45 minutes, or until fork-tender and caramelized at the edges.
Make the couscous. In a large pot, heat 2 tablespoon olive oil over medium heat. Add the onion and cook for about 5 minutes until translucent. Stir in the garlic and cook another 3 minutes. Cook the couscous according to package instructions (mine calls for boiling water first, so I added the cold water to the pot with onions and garlic and boiled from there). Add the salt, cinnamon turmeric, and cumin (if using) when adding the couscous.
Make the dressing. In a small bowl, whisk together the olive oil, Dijon mustard, maple syrup, apple cider vinegar, kosher salt, pepper, and orange zest (if using). Whisk for about 20 seconds until smooth and emulsified. Give this a taste, and adjust for more apple cider vinegar, mustard, or maple syrup as desired.
Combine and serve. Add the roasted vegetables to the cooked couscous, pour the dressing over, and toss well to combine. Garnish with chopped parsley. Serve warm or refrigerate to serve cooled.