Using a stand mixer or an electric hand mixer, cream together the butter and sugars until light in color and fluffy in texture.
Add in the eggs, corn syrup, vanilla and milk. Mix until thoroughly combined.
Next, add the flour, cocoa, cornstarch, baking soda and salt. Mix until your chocolate cookie dough forms. The dough will be soft.
Portion out the dough, as desired. For small cookies, use 1 1/2 tbsp of dough. For medium sized cookies use 3 tbsp of dough. For large cookies, use 1/3 cup of dough. (The photos in this post use 1/3 cup of dough for each cookie)
Roll and press the powdered sugar onto each ball of dough.
Bake at 350° F (180° C) until the cookies have flattened, spread and have started to crackle. For small cookies: bake 7-9 minutes. For medium cookies: bake 9-11 minutes. For large cookies: bake 11-13 minutes.
Allow the cookies to cool on the pan for 10 minutes prior to transfering to a wire rack. While the cookies cool, make the two frostings.
Fudge Frosting
Whip the butter and cream cheese until smooth.
Add the powdered sugar, one cup at a time, mixing until it is combined before adding another cup.
Add the cocoa powder and the vanilla.
Add milk 1 tsp at a time until you've reached your desired consistency.
Peppermint Cream Cheese Frosting
Whip the butter and cream cheese until smooth.
Add the powdered sugar, one cup at a time, mixing until it is combined before adding another cup.
Add in the vanilla and peppermint bakery emulsion and pinch of salt.
Add milk 1 tsp at a time, if needed. (I usually don't need any milk.)
Add a few drops of pink food coloring, if desired.
Assembling the Cookies
First, spread a layer of fudge frosting onto each cookie.
Next, Spread a layer of peppermint frosting onto the top of the fudge frosting layer and immediately sprinkle with crushed peppermint pieces.
Store in the fridge and serve chilled.
Notes
This recipe will make 36 small cookies, 18 medium cookies or 9 large cookies.