Heat the oil in a 4 to 5 quart Dutch oven or stock pot over medium until shimmering. Add the vegetables (onion, pepper, celery, carrots, fennel, and potatoes) and sauté until the onions begin to soften, about 5 minutes. Add the garlic and herbs, and stir until fragrant (just a minute or so). Pour in the diced tomatoes (with the juices) and combine, along with the bay leaf.

Clear a space in the center of the pot by scootching the vegetables to sides of the pot. Place the chicken (or chicken pieces) skin-side down in contact with the surface of the pot and let sizzle for several minutes. Flip so the skin side is up. Cover everything with water by 1" (about 4 cups). Bring the stew to a boil, then reduce heat to medium-low, to maintain a simmer. Stir in 1/2 teaspoon salt, 1/2 teaspoon black pepper and the Parmesan rind (if using a rind). Cover partially with lid, and let cook for two hours.

After two hours, taste the broth, and add another 1/2 teaspoon salt, if needed.

Transfer all of the chicken to a bowl to cool (about 20 minutes), and remove and discard the bay leaf and Parmesan rind (if using). Stir the lentils into the soup and cover again. Cook for at least 15 minutes more.

Meanwhile, prepare the pasta according to package directions (no softer than al dente). Drain, and add to soup.**

When the chicken can be handled safely, remove the meat from the bones and shred (discard the bones or freeze to make broth later). Add to the soup.

If using grated Parmesan cheese, add now and stir in, along with the fresh parsley. Serve immediately, or refrigerate overnight for even more flavor.