In a large stockpot, render the bacon over medium-low heat until crispy, 6 to 8 minutes. Transfer the bacon to a plate and reserve the fat in the pot. Turn the heat up to medium, add the sweet potato to the bacon fat and cook to al dente, 3 to 5 minutes. Transfer the sweet potato to the bacon plate.
Add the garlic, bay leaves, celery, onion, bell pepper, salt and pepper to the bacon fat. Add a tablespoon of butter if there's not enough bacon fat to saute the vegetables. Cook over medium heat until the vegetables are translucent and soft, 5 to 6 minutes.
Add the flour to the pot and stir with the vegetables until fully incorporated. Stir in the vegetable stock and canned corn with its liquid. Bring to a simmer. Add the bacon and sweet potatoes back to the pot and slowly stir in the heavy cream. Cook for a few minutes to warm through.
Garnish with freshly ground black pepper and sliced green onions before serving.