How can I keep hard edges with this shape? I'm unsuccesfully tryning to keep the edges blunt, not too sharp for a more natural render by applying a Subsurf modifier. That's why I don't use the crease of 1. I tried to add an edge loop (CTRL+R) but can't on the top face. Thanks for your help.




Both answers work perfectly except for the following shape. I would like to soften the hard edges of the mesh. Thanks.
The easiest way would be to delete top faces, extrude rim and close the cup in different way, but if you want to keep quads, use bevel edge, by selecting outer edge and pressing CTRL+B and moving mouse to set bevel size.Her are both ways: