Cream together the Earth Balance (or butter) and granulated sugar.
Add the flax egg and vanilla extract, and mix in until incorporated.
In another bowl, sift together flour, soy milk powder, baking powder, and then gradually beat in the dry mixture into the egg/butter/sugar mixture until you get a soft, slightly crumbly dough.
Bring the dough together until you get a big round. Divide into two flat discs and cover in plastic wrap to let chill in the fridge for at least an hour.
Remove from the fridge after 1 hour and roll until 1/4 inch thick and cut into your desired shapes.
Preheat oven to 350F.
You may have to pack and roll gradually as the dough may not like sticking together.
Gently place the cut shapes on a lined baking sheet and chill in the fridge for about 15 minutes before baking to keep the shapes intact.
Bake for 15 minutes until the bottom edges are just barely starting to turn a golden brown. Remove immediately and let cool on a wire rack. Remove from sheet after about 5 minutes, then continue to let them cool on the wire rack.
To make the filling, beat together the Earth Balance/Butter, icing sugar, vanilla extract, and almond milk until light and fluffy.
Transfer frosting to a piping bag with a large 1/2 inch round tip. Pipe a thin layer of icing on the flat side of the cookie, and gently sandwich using another cookie.
Store in an airtight container in the fridge, although these cookies are best enjoyed at room temperature.
