Try this fun spin on sour cream and onion potatoes. The potatoes roast, then "melt," absorbing a savory onion flavor. They're perfect for holidays but simple enough for a weeknight.
Position rack in upper third of oven; preheat to 500°F.
Toss potatoes, butter, oil, salt and pepper in a large bowl. Arrange in a single layer in a 9-by-13-inch metal baking pan. (Don't use a glass dish, which could shatter.) Roast, flipping once, until browned, about 30 minutes.
Whisk broth and onion powder together in a measuring cup. Carefully add the broth mixture to the pan. Sprinkle with onions. Continue roasting until most of the broth is absorbed and the potatoes are very tender, about 15 minutes more. Dollop sour cream evenly on the potatoes. Serve hot.