Ever tried roasting your veggies before making a soup? I do that all the time because I'm too lazy to watch them cook, ahah ;) So for all the slackers like me: you just put everything on a baking tray in the oven, and you can go chill in your bath, on your balcony, at the neighbors', or whatever you want!
Here, it'll be sweet potatoes, because... sweet potatoes, right? No need for an explanation. But feel free to play around with your choice of veggies: squash and bell peppers, cauliflower and nicely roasted potatoes, parsnips...