Jack Vamvas has a process for us:
Steps to restore a database from a backup device that was part of an Always On Availability Group, and now needs to be restored
Recovery Scenario : Requesting an older database copy previously backed up
Name of Always on Availability Group = MyAG1
Name of Always On Availability Group db = MyAGDB1
Note: this is a workflow – and there may be some slight variations depending your Availability Group set up
Read on for rest of the workflow.