This recipe hinges on either my fish stock, or my recipe for fish consomme. You'll need that to start. Walleye is what I use here, but any firm, white fish works. See the headnotes for options.
Cut the fish into bite-sized pieces. Slice any larger cherry tomatoes in half. Chop or tear any greens larger than about the size of a quarter. Slice the serrano thinly.
Heat the broth or consomme to the steaming point, then add the remaining ingredients. Let this steep, or simmer very gently, for about 5 minutes, or until the fish is cooked. Serve at once.
Notes
You can absolutely switch out herbs for the greens, or use both. I like using parsley, lovage, summer savory, fresh oregano or marjoram, cutting celery, or cilantro.