Wash the thyme stalks in hot water for 20 seconds. When cool enough to handle, strip the leaves off the stalk. In a food processor, whiz the thyme leaves, the cumin seeds and orange zest together with the butter.
Lay out a 30cm square piece of greaseproof paper on a work surface and scoop the butter on to the middle. Roll one edge up over the butter as if you were trying to fold the paper in half, and with your hands shape the butter into a cylinder shape as best you can. Wrap the butter up in the paper, twist the ends so the package looks like a Christmas cracker and place in the fridge to set.
Steam the carrots for 10 minutes and, once cooked, toss in a warm bowl with some slices of the thyme, cumin and orange butter.