Preheat the oven to 450°F (230°C) and line a baking sheet with parchment paper or lightly grease with oil.

In a large bowl, combine the halved red potatoes, olive oil, dry onion soup mix, garlic powder, rosemary, salt, and pepper. Toss until each piece is evenly coated.

Spread the potatoes in a single layer on the prepared baking sheet, cut side down for maximum crispiness.

Roast in the hot oven for 35–40 minutes, stirring once halfway through, until the potatoes are golden brown and crisp.

Remove from the oven and let cool for a few minutes before serving. Garnish with fresh parsley if desired.