Preheat the oven to 200C/400F. Pick the carrots that are similar in size and thickness or cut them. Peel them.
In a small bowl mix the maple syrup, melted butter, Dijon mustard and the chilli oil or chilli flakes. The chilli oil is optional.
Line a baking tray with parchment paper for an easy clean up, then arrange the carrots on the tray with a little space between them. Brush the glaze on the carrots, then flip them and brush the other side. (You will have some glaze leftover, set aside for later.) Roast in the preheated oven for 40-50 minutes depending on the size of your carrots.
Remove from the oven and brush with the remaining glaze, season with sea salt before serving.