Preheat oven to 375F/190C. In a small bowl, mix 2 tbsp honey, 2 tbsp balsamic vinegar, 1 tbsp olive oil and a good pinch of salt and pepper.
Trim the roots off your carrots and slice them in half lengthways, to make 2 even-sized, thinner carrots. If your carrots are large, I recommend quartering them. If your carrots are very thin/small, then you can leave them whole. It's important that all the carrots are of a similar size/thickness. (see notes)
In a suitably sized tray, combine the carrots, a few sprigs of thyme and 3/4 of the glaze, ensuring you coat the carrots as evenly as possible. Roast for 15-20 mins or until the carrots just start to caramelize. If at any point you see the vinegar beginning to char on the baking tray, mix the carrots and nudge down the heat.
Take the tray out of the oven, flip the carrots and pour over the rest of your glaze. Pop back in the oven until fully caramelized and sticky. This can take up to another 20-25mins depending on the size of your carrots. Please be vigilant and don't be tempted to whack up the heat. Anything over 400F/200C risks them burning the glaze.
Serve by removing the thyme stalks and sprinkle with fresh parsley. I also recommend another pinch of salt at the end, just the balance out the sweetness. If you particularly love balsamic vinegar then use a brush to flick over some at serving, or if you particularly love honey, then feel free to give them a tiny drizzle.