There seem to be many different techniques to do this.
Here's the scoop - I am going to a dinner party where each couple brings a dish from another part of the world. My country is Morocco. I would also like to bring cookies decorated to look like Moroccan tiles. I was thinking of setting a "frame" around the cookie (on top of the stained glass) to look like a traditional moroccan door/window frame.
So......I will most likely use black Royal Icing for the design base. (or maybe gold?)
But, how should I make the stained glass/tile look?
Tint piping gel?
Simply paint with thinned out gel color?
Any ideas would be much appreciated - thank you!

Also - I have tried looking for good video/photo tutorials, but can't find any. Do you know of any?

if you wanted an actual "glass" i would go with the piping gel! If you were painting with thinned out gel color what would that be painted on? then you would get an opaque look i would think.

I don't know how the piping gel would hold up next to the royal icing tho....i would assume you would have to let that black outline really set. maybe someone else has advice on that!

good luck!

I've used piping gel on royal icing cookies with no problem. You'll want to apply it thinly and as far in advance as possible as it takes a LONG time to dry.

you might try using glace as the "filling" of the glass parts. Glace is much more transparent-looking than RI, so it might give you the look you are going for and still be a tasty option.