Step 1

Position rack in upper third of oven; preheat to 500 degrees F.

Step 2

Toss sweet potatoes, butter, oil, salt and pepper in a large bowl. Arrange in a single layer in a 9-by-13-inch metal baking pan. (Do not use a glass dish, which could shatter.) Roast, flipping once, until browned, 25 to 30 minutes.

Step 3

Whisk broth, maple syrup and lemon juice together in a measuring cup. Carefully add the mixture to the pan. Continue roasting until most of the liquid is absorbed and the sweet potatoes are very tender, 5 to 8 more minutes. Serve hot.