1. Tie 3 sprigs of the parsley, the thyme, and oregano together with kitchen twine. Set aside.
2. Spray a large heavy pot with cooking spray.
3. Drain the beans. Place the beans in the prepared pot Add the herb bouquet and water (or vegetable stock) to cover by 1 inch. Stir and add the clove-studded onion, whole head garlic, and celery. Place over high heat and bring to a boil. Lower the heat to a simmer and Cover. Simmer gently for 40 minutes. Uncover and add 2 teaspoons of the salt. Replace the lid and continue simmering for 30 to 45 minutes longer.
4. Spray a large skillet with cooking spray. Add 1 tablespoon of the oil and place over medium heat. Add both varieties of the soysage along with the vegetarian Canadian bacon and sear, turning as needed until all sides are golden brown, about 4 minutes. Remove the soysages and bacon from the pan and let cool. When cool enough to handle, quarter the bacon and slice the soysage into ¾-inch pieces. Set aside.
5. Add 3 tablespoons of the remaining oil to the skillet. Place over medium heat and add the chopped onions. Sauté until beginning to soften, about 3 minutes. Add the carrots and sauté for another 4 minutes. Lower the heat slightly and add the minced garlic. Sauté for 1 minute, then add the tomatoes, honey, and chile flakes and cook for 10 minutes more.
6. Meanwhile, taste the beans. They should be just barely tender. If so, fish out and discard the clove-studded onion, the celery, and the herb bouquet. Also fish out the garlic, but don’t throw it out—set it aside to cool.
7. Add the tomato mixture to the beans.
8. When the whole garlic has cooled sufficiently to handle, squeeze the garlic pulp into the beans and tomatoes, discarding the skin.
9. Preheat the oven to 300°F.
10. Spray a deep 9½-by-18-inch casserole with cooking spray. Set aside.
11. Combine 1 ladleful of the bean mixture with the whole garlic cloves, leaves from the remaining parsley, and 3 tablespoons of the remaining oil in a food processor. Buzz until smooth, then stir the puree into the beans and season with pepper. Taste the beans for seasoning, adding the remaining 1/2 teaspoon salt, or more if needed.
12. Spoon half of the beans into the prepared casserole. Scatter the soysage and vegetarian Canadian bacon over the top. Spoon in the remaining beans.
13. Toss the breadcrumbs with the remaining tablespoon of oil. Pat the mixture over the top of the beans. Place the cassoulet in the preheated oven and bake until bubbling and aromatic, about 1½ hours. Remove from the oven and raise the temperature to broil. Place the cassoulet under the broiler until the crumb crust is a deep golden brown, 1 to 2 minutes. Serve hot, straight from the casserole.