"If you want an Indian twist on the classic root vegetable bake, then this is a scrumptious alternative. I found that leaving it overnight to cool and then slow cooking it the next day blended the flavors beautifully."
Combine red onions, carrots, sweet potatoes, and rutabaga in a large bowl. Pour in olive oil and butter. Add curry powder, turmeric, salt, and cumin; toss until thoroughly coated. Transfer to a large baking dish.
Bake in the preheated oven, uncovered, until almost tender, 20 to 30 minutes. Toss. Continue baking until vegetables are fork-tender, 20 to 30 minutes more.