Preheat the oven to 350°F.
Prepare two baking sheets with parchment paper, set aside.
In a small bowl, mix up the powdered egg substitute to the package directions and set aside.
Next, in a medium sized mixing bowl, combine and cream together the sugars, oil, and vegan margarine.
Continue by adding and mixing in the egg substitute, vanilla, baking soda, salt, and cream of tartar to the sugars and oils.
Slowly start to add the flour, about 1/2 cup at a time, until well combined.
Once the dough is well combined, fold in the puffed rice.
Spoon the cookie dough, about a 1 1/2 to 2 inch ball, onto the lined baking sheets.
Flatten the cookies with your hand or a bottom of a glass, to about 1/2 inch thickness.
Once you have the baking sheets full, place them into the oven.
Bake for about 6 minutes, then rotate and continue baking for another 6 minutes, baking times can vary, so keep a close eye on the cookies.
The cookies will have a slight golden brown color on the top and edges once done.
Remove the cookies from the oven, leaving the cookies to cool on the baking sheets for about 5 minutes before moving them to a cooling rack.
After the cookies have completely cooled, store in a air tight container.
