Heat the olive oil in a Dutch oven over medium-high heat. Add the sausage and break it into rough chunks with a wooden spoon. Let it sit undisturbed for 3 minutes to take on color, then crumble and stir and keep cooking 7 to 10 minutes total, until the pieces are deeply browned and a little crusty. This browning is the whole flavor of the soup, so do not rush it.

Lift the sausage out with a slotted spoon onto a plate. Pour off the rendered fat, leaving about 1 tablespoon in the pot.

Add the onion, celery and carrot to the pot with a pinch of salt. Cook over medium heat for 5 minutes, scraping up the browned bits from the bottom as the vegetables release moisture, until softened but not browned.

Add the garlic, tomato paste, Italian seasoning, fennel seed and red pepper flakes. Cook 1 minute, stirring constantly, until the paste darkens a shade and the herbs smell fragrant.

Pour in the wine, if using, and scrape the base of the pot clean. Simmer 2 minutes until the sharp alcohol smell is gone.

Add the crushed tomatoes, chicken broth and the browned sausage along with any juices on the plate. Bring to a boil, then reduce to a gentle simmer and cook uncovered for 20 minutes. Taste it now: the broth should taste of pork and tomato, not of raw stock. Season with the salt and black pepper.

Raise the heat to a steady simmer and add the tortellini. Cook just 3 to 5 minutes, following the package time, until the pasta is tender and floats. Do not let it go longer or the seams split and the filling leaks into the broth.

Pull the pot off the heat. Stir in the heavy cream and the spinach; the residual heat will wilt the greens in under a minute. If using kale, stir it in 2 minutes before the tortellini is done instead.

Stir in the grated Parmigiano-Reggiano off the heat so it melts smoothly without stringing. Taste and adjust salt and pepper.

Ladle into warm bowls right away and finish each with more grated Parmigiano and a grind of black pepper.