Heat oven to 200C/180C fan/gas 6. Halve the squash and scoop out the seeds. Put in a microwaveable bowl, cover and microwave on High for 20 mins until softening. Scoop out the flesh with a spoon, reserving the skin, and mix with the remaining ingredients. Spoon back into the skin and transfer to a baking tray. Cook for a further 10-15 mins until tender and the cheese has melted.