Preheat oven to 425. Prepare a baking sheet lined with foil.
You will be tossing the cubed sweet potato, so use a bowl that is large enough to toss the ingredients without them flying out of the bowl.
Add olive oil, sea salt, black pepper and onion powder, rosemary and parsley to the large bowl. Whisk until completely blended.
Add cubed sweet potatoes to the bowl & toss until all pieces evenly coated with the seasoned olive oil.
Arrange the coated sweet potatoes in a single layer on the baking sheet. Place on the middle rack in the oven. Roast for 20 minutes.
Turn the sweet potatoes so they roast evenly. Roast for another 10 – 15 minutes. You will know when the sweet potatoes are done when you see a brown crisp to the edges of the cubes and the pieces are tender.