Top and tail the parsnips, cutting any larger ones in half lengthways.
Put in a large saucepan, cover with salted water and parboil for 5 mins.
Drain well and allow to steam dry for a few minutes.
Pick the thyme leaves. Toss the parsnips with the thyme, honey, a pinch of sea salt and some black pepper. Add the flour plus the parmesan and/or chilli flakes if using and again toss well to coat.
Put in a roasting tin with the oil and butter, and roast for 40 mins, turning halfway, until golden.