Peanut Butter Whoopie Pies

• 3 1/2 cups all-purpose flour
• 1 1/2 cups unsweetened cocoa powder
• 1 tablespoon baking soda
• 1 teaspoon baking powder
• 1 teaspoon salt
• 2 sticks (1 cup) unsalted butter, room temperature
• 2 cups sugar
• 2 large eggs
• 2 cups buttermilk, room temperature
• 2 teaspoons pure vanilla extract
• 1 1/3 cup natural, creamy peanut butter
• 1 cup (2 sticks) unsalted butter, room temperature
• 1 1/2 cups confectioners sugar
• Coarse salt (optional)
• 1 cup plus 1 tablespoon sugar
• 1 teaspoon light corn syrup
• 1/2 cup water
• 4 large egg whites
• 1/2 teaspoon pure vanilla extract

1. Preheat oven to 400F.
2. Make cookies: Line two rimmed baking sheets with nonstick baking mats (such as Silpats), or with parchment.
3. Sift together flour, cocoa powder, baking soda, baking powder, and salt.
4. With an electric mixer, beat butter and sugar on medium speed until light and fluffy.
5. Add eggs, buttermilk, and vanilla.
6. Beat until well combined.
7. On low speed, slowly add dry ingredients; mix until combined.
8. Drop 1 1/2 tablespoons of batter onto prepared baking sheets, spacing 2 inches apart.
9. Bake until set, about 8 minutes, rotating halfway through.
10. (When the top of a cookie is gently touched, it should feel soft but not wet.)
11. Cool completely on a wire rack.
12. Make filling: With an electric mixer, beat peanut butter and butter on high speed until smooth.
13. Reduce speed to low.
14. Add confectioners sugar; mix until combined.
15. Raise speed to high, and mix until fluffy and smooth, about 3 minutes.
16. Season with salt, if desired.
17. Assemble cookies: Spread 1 heaping tablespoon filling on the flat side of 1 cookie.
18. Sandwich with another cookie.
19. Repeat with remaining cookies and filling.
20. Cookies can be refrigerated in single layers in airtight containers up to 3 days.
21. Bring to room temperature before serving.
22. In a small, heavy saucepan over medium heat, combine 1 cup sugar, the corn syrup, and the water; bring to a boil, washing down sides of the pan with a pastry brush dipped in water.
23. Raise heat to medium-high.
24. Cook without stirring until a candy thermometer reaches 230F.
25. Meanwhile, with an electric mixer, beat egg whites on medium speed until soft peaks form.
26. Gradually add remaining tablespoon sugar, and beat until peaks are very fluffy but still soft.
27. When the syrup reaches 230F, reduce mixer speed to medium-low; pour syrup in a steady stream down the sides of the bowl.
28. Increase speed to medium-high, and beat until cool, about 7 minutes.
29. Add vanilla, and beat until fully incorporated.
30. The frosting should be shiny and fluffy and hold stiff peaks.
31. Use immediately.

flour, cocoa, baking soda, baking powder, salt, unsalted butter, sugar, eggs, buttermilk, vanilla, natural, unsalted butter, confectioners sugar, salt, sugar, light corn syrup, water, egg whites, vanilla

Taken from www.epicurious.com/recipes/food/views/peanut-butter-whoopie-pies-389267 (may not work)