Set the new dish in big glob of Plaster of Paris.

Joe wrote:
BZ wrote:
I have one of those ceramic soap dishes that is mortared to the wall
just like the tile, and the soap dish broke. I'd like to remove the
broken one to replace it with a new one, but I'm afraid that when I
remove the old one, it will take off the paper from the wallboard behind
it, leaving a gypsum surface to try and attach the new one onto.

Is there any way I can safely remove the old soap dish without tearing
off the paper underneath?

Your tile may actually be over a cement board base which makes the
problem moot. If it was done over wallboard, losing the paper layer
would be a good thing IMO since the tile thinset will have a stronger
bond to the gypsum. Either way you win, so go ahead and dig out the old
dish and put in a new tile. Good luck.

Joe