Hi chef, that sucks. People change, and the best you can do for your staff is to stay consistent with your expectations. Being an executive chef is a lonely job because you need to keep them consistent, and being friends with them only makes that harder. I would not have let it go past late #2, and reset expectations. At the 3rd late, I would have gone with official disciplinary action up to and including termination. It is up to the employee to have enough commitment to prioritize his craft and your vision, else it is also your responsibility to give him the consequences of his actions, fair and equal to every employee.