Cream shortening and sugar in a stand mixer with paddle attachment (or with hand beaters), at medium-high speed.
Add eggs, vanilla, and peppermint extract. Cream until incorporated. Scrape down edges of bowl and cream again, to make sure it’s well incorporated. Combine dry ingredients separately. Then, slowly add combined dry ingredients to stand mixer, set to low speed. Cream the ingredients well, scrape down bowl, and mix again to make sure it’s all incorporated.
Preheat oven to 350°F. Scoop dough using a small cookie scoop (2-3 tablespoon size). Place cookie scoops onto a large baking sheet, lined with parchment paper. Place in freezer for at least 20 minutes to set dough.
Remove from freezer and bake on a cookie sheet lined with parchment paper or a silicone mat, in preheated 350°F for 6-7 minutes.
To know if cookies are done, look for the top of the cookies to lose their shine and for the tops to be rounded. You can lightly press down the tops of the rounded cookie with the back of a spatula, to form the cookies into a nice circular shape.
Once out of the oven, leave on baking sheet for 10-20 minutes until cookie sets.
Once they’ve set, chill for at least 20 minutes in fridge (or freezer) on a baking sheet, before filling with cream filling.