Preheat oven to 425°F. Meanwhile, line a baking sheet with parchment paper.
In a large bowl, toss the sweet potatoes with olive oil, cumin, chili powder, smoked paprika, and salt.
Spread the sweet potatoes evenly on the prepared baking sheet.
Bake for 25-30 minutes or until the sweet potatoes are tender and lightly browned, flipping once halfway through.
Remove from the oven and transfer to a serving dish.
If desired, garnish with cilantro, scallions, and a dollop of vegan sour cream.