(You won't be preheating the oven just yet because the dough needs to chill. When you do, you will preheat to 375℉) Set the vegan butter out to soften if it is cold and hard from the fridge. It should be soft and cool to the touch - not warm and melty.
Make the flax egg by combining the ground flax with the water. Set aside while you are mixing the other ingredients.
2 Tablespoons ground flax, ⅓ cup water
Measure out the dry ingredients (but not the sugars) into a medium sized bowl. When you measure the flour make sure to "lighten" or sift the flour so that you aren't cramming it into the measuring cup. See the blog post for more details. Add the cornstarch, baking soda, baking powder, and salt to the flour. Mix well.
2¾ cups all purpose flour, 1 Tablespoon cornstarch, 1½ teaspoons baking soda, 1 teaspoon baking powder, ¾ teaspoon salt
Use a mixer to cream together the softened vegan butter, shortening, and almond butter with the brown sugar and the white sugar. The vegan butter should be softened but not melted. Cream until the mixture is light and fluffy and the ingredients have all been incorporated.
½ cup vegan butter, ½ cup shortening, 1 cup almond butter, 1 cup brown sugar, 3 Tablespoons agave nectar, ½ teaspoon almond extract, ¾ cup granulated sugar
Add the vanilla and almond extracts, the agave, and the flax egg mixture. Continue mixing with your mixture until they have been incorporated.
2 Tablespoons ground flax, 2 teaspoons vanilla extract, ⅓ cup water
Sprinkle about half of the mixed flour mixture on the top of sugar/butter mixture. Mix with your electric mixer until mostly mixed, add the rest and mix.
Stir in the slivered almonds.
½ cup slivered almonds
Cover with plastic wrap and set in the fridge to chill for about two hours.
Preheat the oven to 375℉ and prepare two or more baking sheets by lining with parchment paper.
Place the extra half cup sugar in a shallow bowl or plate. Use a cookie scoop or large soup spoon and scoop out the dough. Roll into balls. Roll the balls into the half cup sugar. Place on a cookie sheet with room to spread a little. My cookie sheet holds 12 cookies. Use a fork to make the cross hatch marks or single hatch marks. See the blog post for photos. You will be doing this in several batches so place the dough in the fridge to chill between batches. I use two cookie sheets so that I have one ready to put in the moment one comes out.
½ cup granulated sugar
Cook in a 375℉ oven for 9-11 minutes. The cookies will be lightly golden on the edges and lightly browned on the bottoms. Allow to cool on the pan for about five minutes before removing the cookies to a cooling rack.