Preheat your oven to 200°C/400°F/gas 6.
Wash the squash, then cut it in half with a large, sharp knife (cut off one side and roll the squash on to the cut edge to make it safer and easier). With a large spoon, remove the seeds from the squash. Cut the squash lengthwise into quarters and then cut the quarters in half lengthwise to give boat-shaped wedges of squash. (Quite frankly, it doesn’t matter if you hack it up as long as the pieces are roughly the same shape.) Place the pieces into a roasting tray.
Put the spices into a pestle and mortar and pound them up with a pinch of salt. Scrape them into the tray over the squash, add the garlic, rosemary, bacon and olive oil.
Toss the squash, making sure that all the pieces are well coated with the flavours, and arrange the bacon over some of the wedges. Roast in the oven for about 30 minutes, or until tender. The spicy flavour will cook into the squash, which will crisp lightly, the skin becoming caramelized and chewy.