Cut the chilli in half lengthways, remove the seeds and dice the flesh. (Keep the seeds in if you like the heat.) Put the chilli, garlic, thyme leaves (stripped from the stalks) and salt in a pestle and mortar, and pound until it forms a paste. Put the butter in a bowl, add the paste and mix well.
Almost-slice the bread to the bottom every 3cm and then divide the butter mix among each incision, spreading it over the inner surfaces. Put the bread on a baking tray and