Peel and cube the sweet potatoes into uniform 1-inch pieces.
In a small saucepan over low heat, melt the unsalted butter. Stir in minced garlic and sauté for 1-2 minutes until fragrant.
In a large mixing bowl, combine sweet potatoes with olive oil, salt, black pepper, smoked paprika (if using), and the warm garlic butter mixture. Toss until well coated.
Line a baking sheet with parchment paper or grease it lightly. Spread the sweet potatoes in a single layer on the sheet.
Roast for about 25-30 minutes, tossing halfway through until golden brown and fork-tender.
Once done, sprinkle with fresh rosemary before serving warm garnished with parsley.