Stove Top Method:

Cup of Yum
1. Prep the Sausage: Heat 2 tablespoons of olive oil in a large pot over medium heat. Add the sausage and cook until browned, breaking it into smaller pieces with a wooden spoon, about 5-7 minutes. Remove the sausage and set it aside.
2. Sauté Vegetables: In the same pot, add the remaining olive oil. Add the diced onion, celery, and carrots. Sauté until softened, about 5 minutes. Add the zucchini and garlic, and cook for another 2-3 minutes.
3. Combine Ingredients: Stir in the canned diced tomatoes and cook for 2 minutes. Return the sausage to the pot. Add the chicken stock, lentils, bay leaves, and Parmigiano Reggiano rind (if using).
4. Cook the Soup: Bring the mixture to a boil, then reduce heat to low and simmer. Cover and cook for 45-50 minutes, or until the lentils are tender. Stir occasionally. 
5. Finish the Soup: Stir in the parsley and basil—season with salt and pepper to taste.
6. Serve: Ladle the soup into bowls. Top with freshly grated Parmigiano Reggiano cheese. Enjoy with crusty bread.

Slow Cooker Method:

1. Prep the Sausage: In a skillet, heat 2 tablespoons of olive oil over medium heat. Add the sausage and cook until browned, breaking it into smaller pieces, about 5-7 minutes. Transfer the sausage to the slow cooker.
2. Sauté Vegetables: In the same skillet, add the remaining olive oil. Add the diced onion, celery, and carrots. Sauté until softened, about 5 minutes. Add the zucchini and garlic, and cook for another 2-3 minutes. Transfer the sautéed vegetables to the slow cooker.
3. Combine Ingredients: Add the canned diced tomatoes, chicken stock, lentils, bay leaves, and Parmigiano Reggiano rind (if using) to the slow cooker.
4. Cook the Soup: Cover and cook on low for 6-7 hours or on high for 4-5 hours, until the lentils are tender.
5. Finish the Soup: Stir in the parsley and basil. Season with salt and pepper to taste.
6. Serve: Ladle the soup into bowls. Top with freshly grated Parmigiano Reggiano cheese. Enjoy with crusty bread.