In a medium saucepan with a tight-fitting lid, heat the olive oil and butter over medium heat. Add pork tenderloin: cook for 3 to 5 minutes per side or until browned; remove from pan and set aside.
To the same pan, add the onion; sauté for 7 minutes or until soft then season with salt and pepper.
Add apple slices to the pan; sauté for 5 minutes. Return tenderloin to the pan then stir in calvados, broth and flour; simmer for 40 minutes or until pork is fork-tender. Remove tenderloin from the pan.
Bring skillet liquids to a boil over mediumhigh heat then reduce heat and add cream; simmer for 2 minutes or until slightly thickened.
Serve tenderloin with sauce.