One of my favourite (and easiest!) soups to make is roasted butternut squash and red pepper.
I simply de-seed a butternut squash and two red peppers before roasting in the oven with some garlic and chilli. This may take up to an hour depending on the size of the squash. Once roasted, scoop out the flesh and pop into a food processor, along with the roasted peppers. Add a vegetable stock cube and boiling water and blitz until smooth. You can add as little / much water as you want, depending on how thick you like your soup. I usually get about 4 / 5 servings from this - Syn Free on all plans