The following tied in a cheesecloth:
Thinly slice the onions. Heat the oil slowly in a large heavy-bottomed pot. Cook the onions slowly in the olive oil until tender but not browned.
Meanwhile, either chop the tomatoes reserve the liquid. Mince or mash the garlic. When the onions are tender, add the tomatoes and garlic and stir over moderate heat for 3 minutes. Add the reserved tomato juice and vegetable broth. Bring to a boil and sprinkle in the rice. Add the herbs and saffron. Season to taste with salt and pepper. Simmer, partially covered, for 30 minutes.
Carefully taste for seasoning, adding pinches of sugar to bring out flavor and counteract acidity, and small amounts of tomato paste if needed for color and taste. Remove the herb bouquet if using a cheesecloth.
Whisk all ingredients together and chill before serving. Add a little more soy milk if you need to thin dressing.