Using link_to in the controller, or, how do I embed a link in a string?

For things like flash[:etc], and other dynamic text sent from the
controller, how do you embed links?

I've currently fallen back on actually embedding HTML, but as routes
may change, this doesn't seem like a good practice.

An example of what I'm doing now:
flash[:notice] = "#{@var} added! To remove, see your #{<a
href="...">settings</a>}."

Is there any way to use some kind of link_to here?