Heat your oven to 220°C/Fan 200°C/Gas 7. Halve the squash. Scoop out the seeds. Pop the halves on a baking tray or in a roasting tin. Season with salt and pepper. Roast for 35-40 mins till tender.
Warm a dry frying pan over a low heat. Add the pine nuts to the pan. Toast them for 1-2 mins till they’re golden brown. Keep shaking the pan, pine nuts catch and burn easily. Tip into a bowl.
Break the broccoli into small florets. Peel and slice the onions into thin wedges. Bung them on a baking tray or in a roasting tin. Drizzle with ½ tsp olive oil and season. Put to one side.
Finely chop the parsley leaves. Whisk 1 tbsp balsamic vinegar with 1 tbsp olive oil and some seasoning. Put to one side.
Take the squash out of the oven. Slide the broccoli and onion in. Roast for 15 mins. Put the squash to one side to cool a little.
Bring a pan of water to the boil. Add the spaghetti. Simmer for 8 mins till it’s cooked but not too soft. Drain. While the spaghetti cooks, scrape the flesh out of the squash with two forks.
Warm ½ tbsp oil in a frying pan. Peel and grate or crush the garlic into the pan. Fry on a low heat for 1 min till it smells sweet. Add a pinch of chilli flakes (as much or as little as you like) and the parsley.
Add the spaghetti squash and spaghetti to the pan. Mix everything in the pan with two forks to coat it all in the herbs. Serve with the roast broccoli and onions, dressed with the balsamic and sprinkle over the pine nuts.