Spooky Halloween Whoopie Pies (Easy 45-Min Treat)

Ingredients

• 1 3/4 cups (220 g) all-purpose flour
• 2/3 cup (60 g) Dutch-process cocoa powder
• 1 tsp baking soda
• 1/2 tsp fine sea salt
• 8 tbsp (115 g) unsalted butter, room temperature
• 3/4 cup (150 g) light brown sugar, packed
• 1/4 cup (50 g) granulated sugar
• 1 large egg, room temperature
• 1/2 cup (120 ml) buttermilk, room temperature
• 1 tsp pure vanilla extract
• 1 tbsp black gel food coloring
• 1/2 cup (115 g) unsalted butter, softened
• 1 1/2 cups (180 g) powdered sugar
• 1/2 tsp pure vanilla extract
• 1 (7 oz / 200 g) jar marshmallow fluff
• Orange gel food coloring, as needed
• Black and orange sanding sugar or sprinkles
• Candy eyeballs
• Black rope licorice (optional)