Preheat the oven to 200°C, 400°F, Gas Mark 6.
Cut the squash in half and scoop out the seeds – put the seeds to one side. Cut the squash into bitesize cubes and place in a roasting tin. Drizzle the squash with oil and toss with the chilli flakes, cumin and dried herbs and a little salt. Roast for about 20 minutes, until starting to turn golden.
Meanwhile rinse the seeds, dry thoroughly and toast in a dry frying pan until slightly crisp. Set aside.
Once the 20 minutes roasting time is up, add the onions and tomatoes to the pan with the garlic cloves and return to the oven for another 20 minutes or so until the vegetables are tender and golden. Squeeze the garlic from the skins into a food processor and add the coriander and oil. Blitz until you have a smooth dressing – you may need a little more oil. Season and set aside.
Empty the spinach leaves into a large serving bowl and add the borlotti beans. Carefully add the roasted vegetables, then drizzle over the coriander dressing and toss gently before serving.