For the sausages, remove casing, separate them into ½-inch pieces. If prefer, roll them into little balls. Transfer to a plate.
Bring a medium pot of water to a boil.
Meanwhile, in a large skillet over medium heat, add ½ tablespoon olive oil. Add sausage and cook until golden brown on all sides. Transfer the sausage to a plate lined with paper towels. Use a paper towel to remove most of the grease in the skillet, except 1/2 tablespoon. Add onion and saute for 2 minutes. Add garlic and saute until fragrant, about 30 seconds. Add chicken broth, tomatoes, and heavy cream. Bring to a boil and reduce to a simmer. Cook 10 minutes, stirring occasionally. Season with ½ teaspoon salt and ¼ teaspoon black pepper. Return sausage to the sauce.
Add a pinch of salt in the boiling water. Cook the tortellini according to the direction on package. Drain and add the tortellini to the tomato sauce. Toss well. Add spinach and stir to combine. Cook until the spinach is wilted. Transfer to serving plates. Sprinkle with parmesan cheese if using. Serve immediately.