Mix flour, cooca, baking soda, salt together.
Add in margarine, sugar, eggs, vanilla extract. Add in 2 cups pareve milk.
Refrigerate the batter/dough in a container for a few hours (you can also freeze it to make on a later day and let it defrost in fridge before use)
Pipe or scoop the batter onto cookie sheets lined with parchment paper.
To make cookies the same size- draw lines on the parchment paper.
(I used the Wilton 1A tip for piping and made each cake about 2.5 inches long)
Bake on 400 for 7 minutes. Do not over bake.
You can freeze the cookies in layers with parchment paper in between and do cream another time.
For the cream- beat egg whites until foamy, add in each additional ingredient- beating in between each one.
Use the same piping tip to pipe cream onto cookie.
Place another cookie on top.
They freeze very well, in a container with parchment paper between layers