Slice the carrots diagonally into 1cm/½inch thick rounds.
Heat a small frying pan until hot without adding any oil, and put in the cumin and cardamom seeds (be careful as they may pop). Toast these for a few minutes until they begin to release their aromas.
Take a lidded pan large enough to hold the carrots in one layer if possible. Put in the carrots, spices, garlic, thyme, olive and butter, place the pan over a low to medium heat, and sweat the carrots for 5 minutes.
Add the sugar and a cook for a few minutes more. Add a few drops of water just to cool the carrots down a little, then add the orange zest and place a lid on the pan. Continue cooking until the carrots are tender.
Once cooked, remove the lid and if there is any moisture left in the pan, reduce it until the carrots are nice and slippery. Season with salt and freshly ground pepper and serve.