This light soup celebrates spring. If you have asparagus, add some 1/8^th inch bias cut slices and you have all the local vegetable harbingers of the season. This recipe is more of a guideline, really. Feel free to play with it. You could just add the chard stems to the liquid, but the sautéing brings out sweetness in the stems, and wilting the chard in a separate pan gives a lighter, cleaner flavor to the broth. The fava greens are the tips of the plants, including some of the flowers.  Add mushrooms, carrot shreds, whatever you find.