Vegan Mushroom Gravy This is delicious. You can use half as much onion and mushroom if you prefer gravy with more sauce and less veggie content. 1/4 cup extra-virgin olive oil 1 small onion, finely chopped 8 ounces mushrooms, finely chopped 1/4 cup all-purpose flour 2 cups vegetable stock 1 teaspoon soy sauce, to taste In a large skillet, heat oil over medium-high heat. Add onion and mushrooms; cook, stirring, until nice and soft, 8 to 10 minutes. Stir in flour and cook. Slowly stir in vegetable stock, a little at a time, until a smooth sauce forms. Simmer 2 to 3 minutes until thickened. Season with soy sauce. Season with salt and pepper to taste.