Here's what I did (recipe at bottom of post):
After the dough sat in the fridge overnight (because we ran out of the time the night prior) I used powered sugar to "flour" my rolling pin. I took a little out at a time and flattened it on the parchment paper then used a heart shaped cookie cutter. After I laid them all out on the sheet I dusted them with powered sugar.
After they baked and cooled I used a pastry bag to put the filling on one inside of the cookie. Make sure you have a lot so it goes to the edges when the two cookies are closed.
Lightly press the edges into sprinkles or your choice of decoration.
Indulge!
Whoopie Cookies
Cookies:
1 3/4 flour
1/2 cup Dutch-processed cocoa powder (I used natural b/c I had it on hand)
1/4 tsp salt
1 cup sugar
3/4 cup (1 1 /2 sticks) butter, room temp
1 egg
Filling:
1 cup plu 2 TBL powdered sugar
3/4 (1 1 /2 sticks) cup butter, room temp
1/2 tsp vanilla extract
sprinkles or your choice of decoration
1. Preheat oven to 350 (do not preheat until after your dough has chilled and you are ready to actually bake!). Line two baking sheets with parchment paper.
2. In medium bowl, whisk flour, cocoa and salt together.
3. In a standing mixer bowl beat sugar and butter together until light and fluffy. Add egg and mix well.
4. Add dry ingredients into butter mixture and beat until blended. Refrigerate the dough for an hour or longer.
5. Using dough, scoop 1 tablespoon of dough out and roll into smooth balls. Place the balls onto the parchment paper at least 2 inches apart.
6. Using the bottom of a flat glass, flatten each ball of dough into a 2-inch round circle.
7. Bake until they do not look wet, or for about 11 minutes.
8. Cool on tray for 5 minutes then cool completely on rack.
9. For filling: place the butter in a standing mixer bowl and beat until smooth. Add powder sugar and beat until blended well.
10. To assemble: Spread 2 heaping teaspoons of filling evenly over flat side of 1 cookie to edges. Top with another cookie.
11. Roll cookies in sprinkles or other decoration.
This recipe is adapted from the www.kidscookingco.com. We made these over Christmas there with peppermint filling and rolled in crushed peppermint.