APT - how to install recommended packages after installing with --no-install-recommends switch?

You can run apt-cache show package_you_care_about | grep Recommends.

This will show you all the recommended packages for that particular package. You can then install all the packages there.

For example, with gedit:

apt-cache show gedit | grep Recommends
output: Recommends: gir1.2-gtksource-3.0, zenity, yelp
sudo apt-get install gir1.2-gtksource-3.0 zenity yelp

To find all packages with missing recommended packages:

aptitude search '~RBrecommends:~i'