If using olive oil, saute the onions in the oil over low heat until soft.

(If not using olive oil, place the tomatoes, broth, oregano, onions, salt and pepper in a pan together, over medium-low to medium heat. Cook for 30-45 minutes or until onion is soft)

Once onions soften, add tomatoes, broth, oregano, salt, and pepper and cook on medium-low to medium heat for 30 minutes.

While tomatoes cook, puree the white beans with their liquid in your food processor or blender. Add water as necessary to achieve a thick pudding consistency.

Add the pureed beans to your tomato mixture.

I use a hand blender/emulsion stick to make sure the soup is well blended. But You could just as easily add it to your blender to further combine it.