Put the flour in a small dry frying pan over medium heat and toast, stirring often, until it has darkened evenly to a light brown. Transfer the flour to a blender. Add the walnuts, liquid aminos, lemon juice, garlic, pepper, and 1/2 cup of the vegetable bouillon to the blender and blend until smooth. Add the remaining 1 1/2 cups of the bouillon and blend until smooth. Scrape the mixture into a medium saucepan. Bring to a simmer over low heat, and simmer, stirring often, until the mixture is thickened, about 2 minutes. Serve hot. This was developed especially for the zucchini boats, but is also good over brown rice, potatoes and vegetables.