Cook lardons in a large frying pan over low heat for 10 minutes until crisp and golden.
Transfer crisp lardons to a plate.
Fry carrots, celery, and onion in the bacon fat for 2 minutes.
Add garlic, herbs, and tomato purée and cook for 1 minute.
Incorporate tomatoes and most of the stock, then bring to a boil.
Transfer the mixture to a slow cooker and cook on high for 4 hours.
Stir in beans, pasta, and remaining stock if the mixture is too thick.
Layer shredded greens on top, cover, and cook for 30 minutes until pasta is tender.
Stir in the greens and season with salt and pepper.
Serve in bowls with a drizzle of oil and grated parmesan.