Saute the onion in a little butter or oil until tender.
Combine all remaining ingredients in a pot.Stir well to combine and heat over medium to medium low heat. Stirring occasionally.
Once chowder is heated through, taste and add seasoning to your liking. I added some garlic powder, onion powder, parsley & white pepper to mine.
This could easily be put in a slow cooker and left on low all day as well.