Preheat the oven to 425 degrees. Peel skins and then cube the sweet potatoes into approximately 1” cubes. Lay on paper towels and press to remove excess moisture. Place them in a large bowl.
In a small bowl, whisk the olive oil, salt, pepper, garlic powder, paprika, cumin and cayenne until well combined. Pour the seasonings over the potatoes and mix thoroughly to coat each cube of potato.
Spread the potatoes in a single layer on a large baking tray with sides and place in the oven for 40 minutes. At the halfway point, stir and flip the cubes over so they roast evenly. Remove and garnish with fresh herb of choice (parsley shown) and serve while hot.