Heat the oven to 425°F (220°C), or 400°F convection. Line a large baking sheet with parchment if desired, and allow the pan to heat while you prepare the sweet potatoes.

Peel the sweet potatoes or scrub the skins thoroughly, then cut them into evenly sized 1-inch cubes or wedges. Pat the cut pieces dry with a clean kitchen towel so excess moisture does not interfere with browning.

Place the sweet potatoes in a large bowl and add olive oil, cumin, paprika, cinnamon, cayenne, kosher salt, and black pepper. Add the maple syrup or honey now if you want a sweeter, lightly glazed finish, then toss until every piece is coated.

Arrange the seasoned pieces on the baking sheet in a single layer, leaving space between them. Do not overlap the potatoes, because crowding traps steam and keeps the edges from becoming browned.

Roast for 25 to 35 minutes, turning the pieces once halfway through cooking. Continue until the edges are deeply browned and the centers are easily pierced with a fork.

Taste one piece carefully and adjust the salt or cayenne if needed. Sprinkle with chopped fresh parsley or cilantro, then serve the sweet potatoes warm.