This mushroom leek soup is the perfect example of flexible food.  It cooks up quickly, reheats well, requires very little fuss, and is infinitely adaptable.  If you want it vegan, swap out the chicken broth for vegetable broth and skip the cheese.  If you aim for gluten free, forget the croutons.  If you have a handful of leftover vegetables, you can throw them in the pot.  I added a couple of handfuls of baby spinach because I had it, but it can also be skipped if you don’t.  You can even swap in onions for leeks, but they don’t have quite the same delicacy of flavor.  Many people avoid fennel because they don’t like licorice — here, the licorice notes are all but unnoticeable – the fennel adds a depth of flavor and a hint of sweetness which balances the mushrooms. [...]