Creamy Cod and Mushroom Soup

I adapted this from a recipe on Starlene's blog , and Ben said, "This is my favorite soup for breakfast in the whole WORLD!"

1 cup scallions (or onions), finely chopped
1 lb. crimini or other mushrooms, sliced
3 cups meat stock or broth, divided
2 pounds boneless cod fish, diced into 1″ chunks
1 teaspoon good salt
1/2-1 cup good, raw butter
Minced fresh chervil, optional

Place half the broth in a small pot, bring barely to a boil, add scallions or onions, and simmer for ten minutes. Add mushrooms, and simmer for another ten minutes. Reserve a half-cup of the mushrooms, and using an immersion blender, puree the rest of the vegetable mixture until it is mostly creamy with no large chunks; return the reserved mushrooms to the pot.

Meanwhile, place the cod in the remaining broth in a medium-sized saucepan. Heat until it reaches a simmer, add the salt, and then simmer for 5-10 minutes--until the fish is done. (You will know it's done when the flesh flakes when you press on it.)

Add the vegetable mixture to the cod, stir, and add the butter. Allow the butter to melt, and then add salt and pepper to taste; garnish with fresh chervil if you have any.