Place all ingredients in a large saucepan and cook on medium for 10 minutes. You want to use a large pan since it will splatter if you use a smaller one.
Turn off the heat and blend using an immersion blender. Alternatively, pour into a blender and process until smooth.
Continue cooking for another 10 minutes or until desired thickness. If it's too thick, add a little broth or water. If it's too thin, keep cooking.