Heat oven to 200C. Remove the skin and seeds from the pumpkin and cut into chunky cubes. Place on a baking tray lined with baking paper along with the onion, and drizzle over half of the olive oil. Sprinkle with salt and pepper and place in the oven for 40 minutes or until golden, turning half way through.
Meanwhile, make your dressing by placing the rest of the olive oil, the balsamic vinegar, mustard, garlic and salt and pepper into a small jar. Give it a good shake and set aside.
In a large bowl combine your baby spinach, tomatoes, cashews, and chickpeas. Add the pumpkin once it’s finished roasting, and top with the homemade dressing.