Saute’ onions and garlic in 3-4 tablespoons of water in a medium saucepan. Cook over medium-high heat. Add the mushrooms. Saute’ these until they are slightly tender. This should take about 3-4 minutes. Stir in the flour and cook to mix with the vegetables. The longer you cook the mixture, the browner it will become in color. Whisk in the soy milk until the soup is creamy with no lumps. Add the vegetable broth and seasonings; bring to a boil. Turn heat to medium-low, whisking gently as needed. Continue cooking until the soup thickens to desired consistency—about 7 to 10 minutes. Once the soup is thickened, remove from heat and serve. Leftovers can be stored in the refrigerator up to 4 days.