Whoopie Pies | Bret's Table

Ingredients

• For the Cakes:
• ¼ pound (1 stick) butter, at room temperature
• 1 cup light brown sugar
• 1 large egg
• 1 teaspoon vanilla extract
• 1 ¼ teaspoons baking soda
• 1 teaspoon sea salt
• 2 cups all-purpose flour (I used unbleached)
• ½ cup cocoa
• 1 cup buttermilk (or 1 scant cup whole milk and 1 tablespoon fresh lemon juice)
• For the Chocolate Mocha Buttercream:
• 1 pound unsalted butter, softened
• 7 ounces granulated sugar
• 2 ½ tablespoons water
• ½ tablespoon light corn syrup
• 2 eggs
• 1 egg white
• ½ teaspoon salt
• ½ teaspoon vanilla extract
• 3 ounces sweet dark chocolate, melted with 2 tablespoons water
• 1 tablespoon instant espresso powder
• 1 tablespoon rum or brandy