In a stockpot, melt the butter over medium heat. Add the onions and stir occasionally until the onions are softened but not browned, about 3 minutes. Add the flour and continue to stir for 1 - 2 minutes.
Add the milk, bay leaf, sugar and salt (optional). Turn the heat up slightly until it comes to a very low boil.
Continue to cook, stirring occasionally, until it is slightly thickened, about 10 minutes.
Stir the baking soda into the tomatoes. Add the tomatoes and the basil to the stockpot. Bring it to a low boil.
Remove the soup from the heat and remove the bay leaf. Puree the soup, if desired, using a hand-held (immersion) or standing blender or a food processor. Serve it immediately, refrigerate it for up to 2 days, or freeze it for up to 3 months.
Slow Cooker Directions:
Add all ingredients except the tomatoes and onions to the slow cooker, and whisk until smooth. Add the tomatoes and onions, and cook on low for 8 - 12 hours, or on high for 4 - 5 hours. Remove the bay leaf and purée the soup, right in the slow cooker with an immersion blender if desired, or transfer to a standing blender or food processor to purée (in batches if necessary).
(Slow cooker cooking times may vary—Get to know your slow cooker and, if necessary, adjust cooking times accordingly.)
Do Ahead or Delegate: Chop the onion, or fully prepare and refrigerate or freeze the soup.Scramble Flavor Booster: Add 1 tsp. smoked paprika with the tomatoes and basil.Tip: Haven't we all experienced the frustration of reaching into the fridge to find that someone has finished the last of the milk? In addition to encouraging your family to jot the finished item on the family grocery list, you can keep some shelf-stable soy, rice or almond milk in your cabinet. That way, you won't have to run to your neighbor's house for milk for your coffee or cereal!Nutritional Information Per Serving (% based upon daily values): Calories 248, Total Fat: 8g, 12.5%; Saturated Fat: 5g, 25.5%; Cholesterol: 25mg, 8.5%; Sodium: 286mg, 12%; Total Carbohydrate: 28g, 9.5%; Dietary Fiber: 4g, 14%; Sugar: 9g; Protein: 13gLike this recipe? Check out The Scramble's family-friendly meal plans to see just how simple getting dinner on the table can be!