Place butter in a large pot over medium heat. Add sausage and brown, then add onion, carrot, celery, garlic, tarragon, and thyme.

Sauté for 5 minutes until onions are glassy. Add tomatoes and wine and bring to a boil. Lower heat to maintain a simmer and cook for 5 minutes.

Add the lentils and stock. When mixture is simmering again, cook for 1 hour or until lentils are tender. Stir in the spinach and cook for 2-3 minutes. Season with salt and pepper and serve.