How to recover previous session Safari tabs after option is greyed out?

Mac Pro running Mojave restarted. Previous open safari tabs did not reopen but Safari did launch and then accidentally quit Safari. Reopening safari caused the menu item to reopen previous windows to be greyed out. Is there any chance to still locate my 100 previous tabs from some hidden file in the system? Really wish Apple would adopt this feature from Chrome. I would always save all open tabs as bookmarks just in case except sadly for this time and of course I get hosed. Thanks for any help.