Saute your diced onions in the melted butter until translucent.
Add the remaining ingredients to the pot and bring to a small bubble on low heat. Remove from heat.
Puree the soup using either a blender, an immersion blender or food processor. Return to back to the pot.
Bring soup to a small boil on low heat. Be sure to watch the soup to make sure it does not scorch. Serve with grilled cheese or shredded cheese and croutons.
Notes
Note: I would recommend eating or freezing this soup within a matter of 3-4 days.
Recipe by Michigan from Scratch at https://www.michiganfromscratch.com/homemade-creamy-tomato-soup/