Cook the SausageIn a large pot or Dutch oven, cook the sausage over medium heat until browned and fully cooked. Break it into small pieces with a wooden spoon as it cooks. Drain excess grease if needed.
Sauté the AromaticsAdd the diced onion to the pot and sauté until softened, about 3–4 minutes. Stir in the minced garlic and cook for an additional minute, until fragrant.
Build the BrothPour in the chicken broth and bring it to a gentle simmer. Stir in the basil, oregano, and red pepper flakes if using.
Cook the TortelliniAdd the tortellini pasta to the pot and cook according to the package instructions, usually about 6–8 minutes.
Add Cream and SpinachReduce the heat to low and stir in the heavy cream. Add the fresh spinach or kale and let it wilt for 1–2 minutes. Taste and adjust seasoning with salt and pepper as needed.
Serve and GarnishLadle the soup into bowls and garnish with fresh parsley or grated Parmesan cheese. Serve hot and enjoy!