01 - Preheat the oven to 425°F. Line a large baking sheet with parchment paper.
02 - Peel the sweet potatoes and slice into fries approximately 1/2 inch thick.
03 - In a large bowl, toss sweet potato fries with olive oil, smoked paprika, garlic powder, sea salt, black pepper, and cornstarch if using, ensuring even coating.
04 - Spread fries in a single layer on the prepared baking sheet, keeping them separated for optimal crispiness.
05 - Roast in the oven for 15 minutes, then flip fries and continue roasting another 12 to 15 minutes until golden brown and edges are crispy.
06 - While fries roast, combine Greek yogurt or sour cream, mayonnaise, lemon juice, Dijon mustard, minced garlic, chopped chives or parsley, and season with salt and pepper. Chill until ready to serve.
07 - Serve the hot roasted fries immediately accompanied by the chilled dip.