S'more Whoopies

Directions

1. 1
   Place rack in the center of the oven and prehead to 375.
2. 2
   Line a baking sheet with parchment.
3. 3
   In a medium bowl, stir together both flours, baking powder, and salt.
4. 4
   In a stand mixer (if you have one) fitted with a paddle attachment, beat butter, 4 tablespoons shortening, and brown sugar until light and cream, about 3 minute Add eggs and buttermilk and beat until combined.
5. 5
   In a measuring cup, combine milk, baking soda, and vinegar.
6. 6
   Add this mixture slowly to the batter along with the flour mixture and beat on low speed until completely combined.
7. 7
   Using a spoon or put your batter into a pastry bag fitted with a large round tip or even a ziplock with the tip cut off would work, drop about 1 tablespoon of batter onto your baking sheet, repeat spacing them at least 2 inches apart.
8. 8
   Bake for about 10 min until the cakes begin to brown.
9. 9
   Remove from the oven and let the cakes cool on the sheet for 3-5 min before transferring them to a rack to cool completely.
10. 10
    Make marshmallow cream - In the work bowl of a stand mixer fitter with the paddle beat together marshmallow fluff and shortening, starting on low and increasing to medium speed until the mixture is smooth and fluffy, about 3 minute Reduce mixer speed to low, add confectioner's sugar and vanilla, and beat until incorporated.
11. 11
    Increase mixture speed to medium and beat until fluffy.
12. 12
    Make chocolate ganache - Place your chocolate in a large, heat proof bowl.
13. 13
    Heat the cream in a saucepan over medium heat just until in bubbles.
14. 14
    Pour the heated cream over the chocolate in the bowl and let it sit for about 10 minutes, until the chocolate is melted.
15. 15
    Stir with a whisk until smooth.
16. 16
    Allow the mixture to rest until firm enough to spread, about 2 hours.
17. 17
    Or you can refrigerate it for about 30 min until it is firm enough to spread, shirting every 10 minute.
18. 18
    When cookies are completely cooled and ganache is firmed enough, spread half of cookies with marshmallow cream.
19. 19
    Spread the other half of the cookies with chocolate ganache.
20. 20
    Sandwich together one marshmallow cookie and one chocolate cookie.
21. 21
    Repeat with all cookies.