- 2 ounces unsweetened chocolate, chopped
- 4 ounces semisweet chocolate, chopped
- 1/2 cup unsalted butter (1 stick)
- 1 cup sugar
- 3 large eggs
- 1 teaspoon pure vanilla extract
- 1 cup all-purpose flour
- 1/4 cup natural cocoa powder, such as Hershey's or Scharffen Berger
- 1/2 teaspoons baking powder
- 3/4 teaspoons fine salt
- 18 large marshmallows, (not minis)
- Preheat oven to 375 degrees F. Line a baking sheet with parchment paper or a silicone baking sheet.
- Put the unsweetened and semisweet chocolates and butter in a medium microwave-safe bowl; heat at 75 percent power until softened, about 2 minutes. Stir, and continue to microwave until completely melted, about 2 minutes more. (Alternatively, put the chocolate and butter in a heatproof bowl. Bring a saucepan filled with an inch or so of water to a very slow simmer; set the bowl over, but not touching the water, and stir occasionally until melted and smooth.)
- Whisk the sugar, eggs and vanilla into the chocolate mixture until smooth.
- Sift the flour, cocoa, baking powder and salt into another bowl. Gradually whisk the dry ingredients into the wet ingredients until moistened. Switch to a rubber spatula and finish folding the batter together; take care not to over-mix.
- Use a small cookie scoop or spoon to drop a heaping tablespoon of batter onto the prepared pan. Repeat to make 36 cookies, spacing them about 1-inch apart. Bake until the cookies spring back when lightly touched, about 6 minutes.
- Cool the cookies slightly. Transfer half of the cookies to a rack. Turn the remaining cookies on the pan over, so they lay flat side up. Place a marshmallow on top of each flipped cookie and return pan to the oven. Cook just until the marshmallow begins to soften and puff, about 3 minutes. Cool marshmallow topped cookies slightly, about 2 minutes. Top with the remaining cookies, pressing lightly to make sandwiches. Cool whoopee pies completely on wire racks. Serve.
- Store in tightly sealed container for up to 1 week.