1. Whisk in vegetable stock and simmer for an additional 5 minutes (add more or less stock to obtain desired consistency).
2. In a large skillet or rondo, brown mushrooms in butter until golden brown. Divide in half.
3. Process half of the mushrooms in a food processor. Add to prepared gravy.
4. Add remaining cooked mushrooms. Simmer for 5-10 minutes, stirring frequently to prevent sticking.
5. Ladle desired amount into serving bowl and garnish with green onions.