Not really focused on coffee. Their special is hot chocolate. You´ll get probably the thickest hot chocolate in your life. They serve diferrent kind of chocolate (country of origin, percentage of cocoa content).
adress:
Liliová 4/250
110 00 Praha
gmaps: goo.gl/maps/zsoi6
closest station: Můstek or Staroměstská (both green metro line "A")