Wash and thoroughly dry the baby potatoes, then slice them in half. Add the potatoes to a large bowl and drizzle them with olive oil. Season with ranch seasoning, garlic powder, onion powder, salt and pepper. Toss everything together until the potatoes are evenly coated in the oil and seasonings.
Arrange the potatoes in a single layer on a baking sheet with the cut sides facing down. Roast for 25-30 minutes, tossing or flipping about half way through, until golden brown and tender. Garnish with chopped fresh parsley, if desired, and serve warm.