defaults write com.apple.dock persistent-others -array-add '{ "tile-data" = { "list-type" = 1; }; "tile-type" = "recents-tile"; }'
killall Dock

There are sev­eral addi­tional options for that icon when you right click, includ­ing Remove from Dock, Recent Doc­u­ments, Recent Server, Favorite Vol­umes and Favorite Items.