Preheat oven to 400 degrees F.

Make harissa ranch. Combine Greek yogurt, buttermilk, chives, dill, harissa, garlic powder, and onion powder in a medium bowl. Whisk until well combined. Season with salt and pepper and let sit for 30 minutes.

Toss sweet potatoes with olive oil, rosemary, paprika, onion powder, salt, and black pepper until well coated. Spread sweet potatoes in an even layer on a baking sheet. Roast sweet potatoes for 25-30 minutes or until browned, flipping over the sweet potatoes halfway through.

Meanwhile, make garlic honey glaze. Melt butter in a small saucepan over medium heat. Add garlic and sauté for 30 seconds. Add honey and red chili flakes and bring to a simmer. Continue to simmer for 2 minutes or until slightly thickened. Remove from heat.

Drizzle garlic honey glaze on sweet potatoes, gently tossing to coat. Transfer sweet potatoes to serving plate and sprinkle chopped hazelnuts and parsley on top. Serve with harissa ranch.