1In a Dutch oven, over medium heat, saute onions in butter until translucent. Remove from the heat. Stir in the flour so that no lumps remain, then slowly whisk in the tomato juice. Return to the heat and add salt to taste. Cook until just boiling but turn off the heat before it boils. Let cool 10 minutes then slowly stir in milk. Serve immediately.
Footnotes
Easy Cleanup
Try using a liner in your slow cooker for easier cleanup