Preheat oven to 350 degrees Fahrenheit. Line two large baking sheets with parchment paper and set aside.
In a large bowl, cream butter and monk fruit sweetener together until fluffy using hand mixer. Add flax egg, peppermint extract, and OWYN 20g Dark Chocolate Protein Shake, mix until combined.
Sift the gluten free all-purpose flour, cocoa powder, baking soda, and salt over the wet mixture. Using the silicon spatula, mix to combine until well blended.
Scoop the cookie dough in 1-inch balls and transfer to the prepared baking sheet. Bake for 10-12 minutes until done.
Let them cool for 5 minutes on the baking sheet and transfer to the wire rack until completely cooled. Meanwhile, prepare the vanilla frosting.
Sift powdered monk fruit sweetener and arrowroot starch into a bowl.
In a large mixing bowl, cream the butter until fluffy for 5-6 minutes using hand mixer or a stand mixer. Slowly add powdered monk fruit sweetener mixture to the butter, one tbsp at a time.
Once all the sweetener is added, add vanilla extract, oat milk and a pinch of salt. Continue to mix until creamy.
Spread a thin layer of the vanilla frosting over the cooled Dark Chocolate Peppermint Protein Cookies. Sprinkle with crushed peppermint candies on the top of vanilla frosting. Let the frosting set for few minutes and serve. Enjoy!
Flax Egg Preparation (For 1 flax egg)-
In a small bowl, mix 1 tbsp of flax seed powder with 3 tbsp water. Let it set for 5-10 minutes. Use this mixture in place of one regular egg.