1. Heat oil in a large stock pot over medium-high heat; add onions and celery and sauté until translucent, about 5-7 minutes.
2. Add garlic and sauté for one more minute.
3. Carefully pour in stock and scrape bottom of the pan to release any brown bits. Stir in the Black Bean Soup
4. Mix and tomatoes.
5. Add the butternut squash and roasted corn.
6. Add herbs, stir and bring to a boil. Once boiling, reduce to a simmer, cover with a lid and cook for 1 1/2 hours, stirring every 1/2 hour to prevent sticking.
7. Add more stock or water if beans and squash absorb too much liquid.To roast corn: It is convenient to use frozen corn, however, fresh was still available, so I chose to use it. Preheat oven to 350°F.
8. Spread frozen corn on a lightly greased cookie sheet and roast in oven for 15-20 minutes stirring occasionally.
9. Remove from oven and cool.