Preheat oven to 350F degrees. Line 2 baking sheets with parchment paper.
Combine ⅓ C milk and apple cider vinegar. Stir and let sit while you prepare the remaining ingredients.
⅓ Cup Non-Dairy Milk, ½ teaspoon Apple Cider Vinegar
Combine the flour, baking powder, baking soda, salt and lemon zest in a medium bowl. Stir well until mixed.
1 Cup + 2 tablespoon Gluten Free 1-to-1 Flour Blend, ½ teaspoon Baking Powder, ¼ teaspoon Baking Soda, ¼ teaspoon Salt, ½ teaspoon Lemon Zest
Combine butter and sugar in the bowl of an electric mixer. Beat on medium speed for 3 minutes until light in color and fluffy in texture. Scrape down the bowl.
⅓ Cup Vegan Butter, ½ Cup Sugar
Add the vanilla, almond extract and egg. Beat for another 60 seconds. Scrape down the bowl.
1 teaspoon Vanilla, ½ teaspoon Almond Extract, 1 Egg
Turn the mixer to the lowest setting. Add half of the flour mixture, followed by half of the soured milk. Repeat with the remaining ingredients. Stir until just combined.
Scoop batter into ¼ cupfuls and drop onto prepared baking sheet leaving 3-4 inches between each mound. The cookies will spread a good bit when baking.
Bake in preheated oven for 13-14 minutes until edges are set. Remove from oven and cool on the baking sheet for 3 minutes, then transfer to a wire cooling rack.
Cool cookies completely before icing.
For the fondant icing
Combine the powdered sugar, milk, corn syrup and vanilla in a small bowl. Whisk until smooth. Icing should be thin enough to spread, but thick enough to hold a ribbon briefly when drizzled into the bowl. Err on the side of too thick, as it is easy to add more liquid.
Working one at a time, flip the cookies over and ice half of the bottom side of each cookie. Lay the half frosted cookies on a rack to dry. It will take about 20 minutes for the icing to dry to the touch.
Cover the vanilla icing bowl while waiting for the cookies to dry to keep the fondant from drying out.
Once the vanilla side has dried, add cocoa powder to the remaining vanilla icing. If it's too thick, add milk 1 teaspoon at a time to thin to desired consistency.
2 Tablespoon Unsweetened Cocoa Powder
Use a spatula to ice the second half of each cookie creating a line in the center. Allows cookies to dry completely before storing.