One of the best things about autumn is that Brussels sprouts come into season. Here is my fav soup to make with them:
I chop up
1 clove of garlic
and any other vegetables that you feel like,
300-500 grams of Brussels sprouts. (I go for the more option normally).
I boil water, add 2 cubes of veg stock and all the vegetables, cook for about 20 minutes. I like to make it a thick soup, a bit like minestrone. You may want to jazz it up with some olive oil, but this is great without that too.