Instructions

  1. Heat the oil in a medium size skillet over medium heat. Add the onion, cover, and cook until softened, about 5 minutes.
  2. Transfer the onion to a 4 quart slow cooker. Add the bell pepper, both kinds of tomatoes, beans, and stock; season with salt and pepper, cover, and cook on low for 6-8 hours.
  3. Just before serving, stir in the pesto. Adjust seasoning.