Preheat the oven to 400.
On a large sheet pan or in a large casserole dish, arrange your carrots in a single layer.
In a small bowl, whisk the butter, oil, cider vinegar, cardamom and salt.
Drizzle the glaze over the carrots. Using clean hands, coat the carrots with the mixture making sure it moistens all sides.
Roast in the oven for 30 - 40 minutes, depending on the size and thickness of your carrots, until they are tender and browned around the edges. Turn them halfway through the roasting process always leaving them in a single layer.
Remove carrots from the oven and allow to rest for 5 minutes before serving.