Preheat the oven to Gas Mark 6, 200°C, 400°F.
Cut the two squash in half, remove the pips with a spoon and discard. Scoop out some of the flesh (leaving a 1cm border) and roughly chop.
Place the squash halves on a roasting tray, season, drizzle with ½ tablespoon of oil. Roast for 40 minutes until tender.
Sauté the onion and chopped squash for 7 minutes until golden. Add the garlic and sauté the mixture for 3 more minutes.
Spoon the mix into the squash cavities, scatter with the feta cheese, pine nuts and chilli, season with salt and pepper and roast for another 10 minutes until the pine nuts are golden. Scatter with the mint leaves.