Beat together first 5 ingredients until smooth.
Mix in egg replacer mixture and vanilla.
Add in flour blend, xanthan, soda, and salt. Mix well.
Drop onto parchment lined cookie sheets by rounded teaspoons.
Flatten with fork. (If the fork sticks to dough, wet fork tines before pressing).
Bake at 375 for 10-11 minutes.
Let cool on cookies sheets for 5 minutes before transferring to wire rack.
Beat the shortening.
Add remaining ingredients.
Mix well until the icing is smooth.
Pipe onto cookies.
(I used a ziploc baggie with a small hole cut in one corner. I'm really high-tech like that....)
NOTE: You could probably make these with sunbutter or another safe "butter" but you might need to reduce the salt. The No Nut Butter does not contain added salt, so I made sure the recipe had enough. You might stick with 1/4 tsp salt if using a different nut or seed butter. You'll have to do a taste test!