Add dried mushrooms to boiling water and let steep for at least 10 minutes, until water is dark brown.
Drain off mushrooms. Discard them or finely chop and add back into gravy later. Melt butter and oil together in a medium, nonstick saucepan over medium heat. Add flour and whisk until smooth and thick.
Whisk in mushroom liquid and vegetable broth and heat just to boiling. Add remaining ingredients, whisk and simmer another 5 to 7 minutes. If returning chopped mushrooms to gravy, do so now.
Servings: 3 cups