In a large Dutch oven or heavy-bottomed pot, cook the Italian sausage over medium-high heat until browned, breaking it into small crumbles.
Drain all but 1 tablespoon of the fat from the pot.
Add the diced onion to the pot and sauté for 5 minutes until softened and translucent.
Stir in the minced garlic, sage, thyme, and red pepper flakes, cooking for 1 minute until fragrant.
Add the cubed butternut squash and chicken broth to the pot. Bring the mixture to a boil.
Reduce heat to medium-low and simmer for 12 to 15 minutes, or until the butternut squash is fork-tender.
Add the refrigerated cheese tortellini to the pot and cook according to package directions, typically 3 to 5 minutes.
Stir in the chopped kale and heavy cream. Cook for 2 minutes until the kale is wilted and the soup is heated through.
Season with salt and black pepper to taste and serve immediately.