Heat the olive oil and butter in a large pot over medium heat. Add the onion, leek and celery and cook for 4-5 minutes, stirring occasionally, until softened. Add the garlic, a pinch of salt and red pepper flakes, if using, and cook for another minute until fragrant.
Pour in the white wine, if using, and scrape up anything from the bottom of the pot. Let it simmer for about 2 minutes to reduce slightly. If you’re skipping the wine, move directly to the next step.
Add the crushed tomatoes and stock and stir to combine. Bring the soup to a gentle simmer, then add the Parmesan rind. Reduce the heat to low and simmer uncovered for about 30 minutes, until the broth has reduced slightly and thickened.
Remove and discard the Parmesan rind. Add the tortellini directly to the soup and cook according to the package instructions.
Reduce the heat to low and stir in the heavy cream, followed by the rotisserie chicken and kale. Cook for another 2-3 minutes, just until the chicken is warmed through and the kale has softened.
Taste and season with additional salt and freshly cracked black pepper as needed. Ladle into bowls and finish with shaved Parmesan, fresh basil and red pepper flakes, if you like.