I originally thought of using white glue and pouring glitter over it. I went shopping for supplies and, lo-and-behold, a whole section of glue at the craft store. Change of plans! I bought a bottle of glitter glue and puffy paint to experiment with. I printed a snowflake pattern from Autumn Carpenter blog site but you can also create one relatively easily. Snowflakes are so diverse, you can't go wrong as long as they are symmetrical. If you are an expert cookie decorator, you can even freehand the snowflakes.
Lay a sheet of wax paper on top of your pattern and tape the sheets down. Turn the glue bottle upside down and tap a few times to get to glue down to the tip to remove any air bubbles. Open the cap and squeeze steadily over the pattern.
Once done, you can go over any area that may not have enough glue. Remember, you will be peeling the snowflake out so you want to have a thick piping. With the delicate pattern I used, I could also fill in areas to create and more solid snowflake.
Here's the puffy paint snowflake.
The hardest part is waiting patiently for the glue to dry. I kept watching it and checking on it. I did add a few drops of glitter glue here and there because the glue thins out as it dries. The best thing to do is to leave it overnight to allow the glue to completely dry. Then you are ready to slowly peel and decorate.
Just to see how it would work, I tried adhering the glitter glue to the window. Glitter glue flattens as it dries and is not as tacky as puffy paint so it did not stick as well but it still looked beautiful.