Heat olive oil in a large Dutch oven over medium heat. Add the carrots, celery, and onion and saute until beginning to soften, about 3 minutes.
Push the veggies to the side, and add the ground beef to the skillet. Saute a few minutes without stirring, then stir everything together and continue to saute another 3-4 minutes, or until beef is no longer pink. Drain off any excess grease.
Add the garlic, red pepper flake and salt and pepper to taste. Saute 1 minute, until fragrant.
Stir in a splash of the chicken broth, deglazing the pan. Add the remainder of the chicken broth and basil, and bring to a boil.
Add the ravioli, stirring gently, and boil for 4 minutes.
Lower the heat to medium low, then stir in the cream and spinach. Heat through, until spinach is wilted. Squeeze half a lemon into the soup. Taste, and add additional lemon juice if desired. Serve with Parmesan cheese and additional red pepper flakes, if desired.