Chickenless Gravy

• 3 cups boiling water
• 2 Tbsp oil
• 4 Tbsp nutritional yeast
• 1 bouillon cube (vegetarian)
• 1/2 - 3/4 cups diced mushrooms
• 1 cup finely chopped onion
• salt to taste
• flour

In a large saucepan, simmer all ingredients except the flour for 5 minutes. Slowly add the flour (by tablespoons), whisking after each addition, until the desired thickness is reached. Keep warm on low heat.