Chocolate Whoopie Pies with Salted Caramel Frosting

Bahan-bahan (15 porsi)

• 2 cups (250g) all-purpose flour (spooned & leveled)
• 6 Tablespoons (32g) unsweetened natural cocoa powder
• 1 and 1/4 teaspoons baking soda
• 1/2 teaspoon salt
• 1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature
• 1 cup (200g) packed light brown sugar
• 1 large egg, at room temperature
• 1 and 1/2 teaspoons pure vanilla extract
• 1 cup (240ml) buttermilk, at room temperature*
• 1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature
• 1 cup (200g) packed light brown sugar
• 5 – 6 Tablespoons heavy cream, divided*
• 1/4 teaspoon salt
• 2 and 1/2 cups (240-300g) confectioners’ sugar, sifted