Fill a pot with salted water and cook tortellini to package instruction. Drain and rinse with cold water until ready to be added to broth.
In a pot over medium heat, cook the bacon until most of the fat has rendered. Add the onions, red pepper flakes and collard greens. Cook for 4-5 minutes. Add parmesan rinds and broth. Simmer for 30-45 minutes. Add kosher salt and apple cider vinegar. Adjust seasonings if need be.
Add cooked tortellini to the broth and cook until heated through. Serve with grated parmesan and enjoy!