I accidentally removed "edit" menu in the NSMenu of my OS X app. Now neither Cmd+X nor Cmd+V works.
I did not find a special 'edit' menu in the interface builder's toolbox.
What's the best way to bring back my beloved edit menu?
Easiest way is to create a new Main Menu template.
Go to File->New->File...
Select OS X -> User Interface -> Main Menu
This will generate a new MainMenu.xib
for you, which includes your edit menu.
Just copy paste the edit menu view from the new file into your old MainMenu, and you're good