Preheat your oven to 425°F (220°C). Line a large baking sheet with parchment paper or lightly oil it — this helps the cubes crisp without sticking.
Wash and peel the sweet potatoes if you prefer them peeled. Cut them into even 1-inch cubes so they roast uniformly. Pat the cubes dry with a clean kitchen towel to remove excess moisture.
Place the cubed sweet potatoes in a large mixing bowl. Drizzle with olive oil, then add salt, pepper, paprika, and ground cumin. Toss gently but thoroughly until each cube is lightly coated. If using maple syrup or honey, add it now for a caramelized, sweet finish.
Spread the seasoned sweet potato cubes in a single layer on the prepared baking sheet. Avoid crowding — leave a little space around each cube so hot air can circulate and create crisp edges.
Roast in the preheated oven for 25–30 minutes, flipping once halfway through (around the 12–15 minute mark). Look for golden-brown edges and fork-tender centers. If you want extra crispiness, broil for 1–2 minutes at the end, watching closely so they don't burn.
Remove from the oven and let the cubes rest on the baking sheet for 3–5 minutes. Transfer to a serving dish, sprinkle with chopped parsley and optional red pepper flakes, and serve warm.
Leftovers can be reheated in a 400°F (200°C) oven for 8–10 minutes to restore crispness, or reheated gently in a skillet with a splash of oil.