Preheat oven to 350°F.
Prepare two cookie sheets with parchment paper.
Mix up the egg replacer to the package directions and set aside.
In a medium mixing bowl, combine and cream together the sugars, oil, and vegan margarine.
Start to add the egg replacer, vanilla, baking soda, salt, and cream of tartar, mixing while adding.
Slowly add the flour, about 1/2 cup at a time, until well combined.
Lastly, you will fold in the puffed rice, stirring until well incorporated.
Spoon the cookie dough onto the lined cookie sheets.
Flatten the cookies with you hand to about 1/2 inch thickness.
Once you have the cookie sheets full, put into the oven.
Bake for about 6 minutes, then rotate the sheet in the oven and continue baking for another 6 minutes.
The cookies should be slightly brown on the edges.
Let the cookies cool on the cookie sheets for about 5 minutes and move to a cooling rack until completely cool.
Store in a air tight container.
Serve these cookies with your favorite hot beverage or with a tall glass of a cold beverage of your choice.