Preheat the oven to 350 degrees
Place parchment paper onto a cookie sheet and set aside
Using a standing mixer, cream together the butter, sugar, brown sugar, and shortening and mix until combined
Add the egg and mix until combined
In a large bowl, using a whisk mix in the flour, baking powder and salt.
Gradually add the flour mixture into the wet mixture until combined
Using an ice cream scoop, scoop some cookie dough into your hands and roll into a ball
Roll cookie dough ball into the sugar and then place onto the cookie sheet
Repeat the steps for 11 more cookie dough balls
Use a fork to flatten cookies a bit in a criss-cross pattern
Bake in the oven for 5 minutes
Pull the cookies out and place each marshmallow on the cookie
Bake for another 5 minutes or until the marshmallow is lightly toaster
Pull cookies out and place unwrapped Hershey kiss into the center
Let cool completely before enjoying!