Heat oil in a saucepan over medium heat.
Saute mushrooms, onion, and garlic until soft and translucent, about 5 minutes.
While sautéing these ingredients, "toast" your dry nutritional yeast in another saucepan for 1 minute, over high heat. Set Aside.
After onions and garlic are translucent, stir in flour, nutritional yeast and soy sauce to form a smooth paste. Gradually whisk in the broth. Season with salt and pepper to taste.
Bring to a boil. Remove half of the gravy and place in a high speed blender until completely blended. Return to sauce pan.
Reduce heat and simmer, stirring constantly, for 8 to 10 minutes, or until thickened.