The first ingredient is tears. Lots of tears. Human tears expressed at the height of sorrow will comprise the majority of this soup. Now here is the problem. How to get them. If you are making Sad soup you are obviously not sad. How could you be? Sad Soup is delicious to eat and exhilarating to prepare. It is impossible and possibly illegal to frown while making Sad Soup.
Now then, There are many ways to get fresh human tears. One of the easiest ways is to observe funerals. Keep your eye out for inexpensive funerals with young crying widows. Because the funeral is cheap, it probably means the widow is having financial trouble and could barely afford the funeral in the first place. Bills are probably piling up and she would be much more apt to take your hard earned money in exchange for her constant grieving tears than a widow with a large inheritance. Just keep offering her money to collect her tears and remind her about her husband any chance you get.
If trolling funerals isn't your bag, why not try Ebay? I have purchased tears many times on Ebay, always from verified sources. There are Sad Soup aficionados across the globe. We are quite a friendly and welcoming community. There is always Sad Souper with ingredients to sell buried within the tastiest depths of Ebay. You just have to look.
Can't afford to pay a widow or Ebay? Well, this is always a last resort for me.... There is always.... Kidnapping. You won't believe how much a person cries when they've been kidnapped. Nonstop. I'm a big fan of the night vision goggles and dark room approach. With your abductee comfortably tied to a chair, you can really get the waterworks flowing with the sound of a chainsaw. I am also a big fan of sharpening knives and laughing. Continue collecting the tears until you get enough for your recipe. Be sure to keep your tear supplier well hydrated! Once you have enough tears, release your abductee unharmed far from your home and worry not. Your abductee will have a great story to tell at parties for the rest of their lives.
The problem with kidnap tears, while easy and cheap to procure, is that they are mostly "Terror Tears", which is not exactly the same thing as "Sorrow Tears". While they both taste very similar, a true gourmet would easily be able to tell the difference.
After procuring the precious tears you can finally make the soup! Everybody has their own recipe. I heat my tears to near boiling on the stove. Do not boil, it will evaporate the sorrow. Once an acceptable temperature is reached I garnish with a parsley sprig and serve. Mmmm, lightly salty..... During the holidays, I add a little clove instead of parsley, so festive. Experiment away and come up with your own tasty recipe. ~Enjoy