1 tablespoon coarsely chopped fresh rosemary leaves (from about 3 sprigs)
2. Stir 2 tablespoons melted unsalted butter, 2 tablespoons olive oil, 3/4 teaspoon kosher salt, and 1/2 teaspoon black pepper together in a large bowl until combined. Add 2 pounds cut sweet potatoes (peeled if desired) and 1 tablespoon coarsely chopped fresh rosemary leaves, and toss well to coat.
3. Transfer the potatoes cut-side up to a 9-by-13-inch metal baking pan (avoid glass, as it could shatter) or rimmed baking sheet (quarter sheet pan) and arrange in a single layer. Drizzle any remaining butter mixture over the potatoes.
4. Roast until the sweet potatoes easily release from the pan with tongs and the bottoms are light golden-brown, about 15 minutes. Flip the rounds and roast until the bottoms and tops are deep golden-brown, about 15 minutes more.
5. Remove the pan from the oven. Carefully pour 1 cup low-sodium vegetable broth into the pan and add four peeled and smashed garlic cloves. Return to the oven and roast until the potatoes are very tender and most of the broth is absorbed, about 15 minutes.
Recipe note: Leftovers can be refrigerated in an airtight container for up to five days..