Preheat the oven to 190℃ (170℃ fan)/375°F/gas mark 5. Place the prepared vegetables in a shallow roasting tin and drizzle with the oil. Roast in the oven for 20 minutes.
Allow the vegetables to cool a little. when cool enough to handle, peel the peppers if desired, I didn't. Place in a large saucepan.
Peel the squash, and cut into large junks, add to the saucepan, along with the onion and garlic.
Add 1 litre (2 pints/4¼cups) water to the pan and add the stock cube and chilli flakes if using. Bring to the boil, then reduce the heat and simmer the vegetables for about 20 minutes or until soft.
Purée the soup (see the body of the post). Season to taste with salt and pepper an reheat gently if required. Serve garnished with some feta cheese, pumpkin seed and a swirl of olive oil
The soup freezes well for up to 4 months.Nutrition information is calculated using an online nutrition database - is approximate and is meant as a guideline only. (It does not include seasoning with salt and pepper or garnish.)