Preheat the oven to 400°F (200°C). Line a large baking sheet with parchment paper.
In a large mixing bowl, combine the sweet potatoes, carrots, bell peppers, and onions.
In a small mixing bowl, whisk together the olive oil, honey, cumin, coriander, paprika, cinnamon, cayenne pepper, salt, and black pepper.
Pour the spice mixture over the vegetables and toss until they are evenly coated.
Spread the vegetables out in a single layer on the prepared baking sheet.
Roast in the preheated oven for 25-30 minutes, or until the vegetables are tender and lightly browned.
Serve hot, garnished with chopped parsley or cilantro if desired.