Melt the butter in a large pot over medium-high heat
Add the onion, carrots, and celery and cook, stirring, until the onion is translucent, about 5 minutes
Stir in the garlic and cook until fragrant, 1 minute more
Sprinkle with the flour and stir until incorporated
Add in the chicken stock, salt, pepper, Italian seasoning, paprika, cream, and parmesan; cook, stirring, until fully incorporated
Bring to a boil, then reduce the heat to medium low simmer until slightly thickened, about 10 minutes
Stir in the chicken, tortellini, and spinach
Cook until the spinach is wilted, the tortellini is tender, and the chicken is warmed through, 3-5 minutes.Ladle the soup into bowls
Serve sprinkled with Parmesan and red pepper flakes, if desired.
