Preheat oven to 375/190c. In a small bowl, mix 2 tbsp honey, 2 tbsp balsamic vinegar, 1 tbsp olive oil and a pinch of salt and pepper.
Trim the tips off your carrots and slice in half lengthways, to make 2 even and thinner carrots. If your carrots are large then quarter them. If your carrots are very thin/small then you can leave them whole. It's important that all the carrots are similar size/thickness. (see notes)
In a suitably sized tray, combine your carrots, a few sprigs of thyme and 3/4 of your glaze, ensuring you coat the carrots as evenly as possible. Roast for 15-20 mins or until the carrots 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 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 390f/200c risks 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.