Managing personal Outlook.com account settings, security, and privacy
Hello
Did you close the entire Microsoft account a year ago? If so, this action is permanent once the closure is beyond the grace period window you set (either 30 or 60 days), and the account/outlook.com address cannot be recovered. Microsoft doesn't allow recycling username, hence you cannot recreate it either.
However if you gave your Microsoft account a different alias, and removed the outlook.com address as an alias within the Microsoft account, then there might be a chance you could still add it back. To do so, sign into the same Microsoft account with the other alias, then go to Your info > Sign in preference > Add an email > Use the "create new" option.