Ingredients:

  • 1 cup (120 g) All-Purpose Flour
  • ½ cup (50 g) Unsweetened Cocoa Powder (natural or Dutch process)
  • 1 teaspoon (5 g) Baking Soda
  • ½ teaspoon (2.5 g) Salt (fine sea salt)
  • ¾ cup (150 g) Granulated Sugar
  • ½ cup (113 g) Unsalted Butter, softened (divided)
  • 2 large Eggs, room temperature
  • ½ cup (120 ml) Buttermilk, room temperature
  • 1 teaspoon (5 ml) Vanilla Extract (divided)
  • 1 cup (240 g) Creamy Peanut Butter (standard type)
  • 2 cups (240 g) Powdered Sugar (Icing Sugar)
  • 1–2 tablespoons (15–30 ml) Milk or Heavy Cream
  • 6 oz (170 g) Dark Chocolate (chips or chopped baking bar, 60–70% cacao)
  • 1 tablespoon (15 ml) Coconut Oil or Vegetable Shortening (optional)

Instructions:

  1. Preheat oven to 350°F (175°C). Line a standard 12-cup muffin tin with cupcake liners.
  2. Combine Dry Ingredients: Whisk together the flour, cocoa powder, baking soda, and salt in a medium bowl. Set aside.
  3. Cream Butter and Sugar: In a stand mixer, beat the softened butter and granulated sugar until light and fluffy (about 3 minutes). Beat in the eggs one at a time, followed by the vanilla extract.
  4. Alternately Mix Dry/Wet: Reduce speed to low. Add half of the dry ingredients, followed by the buttermilk, and then the remaining dry ingredients. Mix only until just combined; do not overmix.
  5. Bake: Scoop batter evenly into the liners (filling about 2/3 full). Bake for 20–22 minutes, or until a toothpick inserted into the centre comes out with moist crumbs attached. Transfer immediately to a wire rack and cool completely (this is crucial before assembly).
  6. Prepare the Peanut Butter Center: In a clean mixing bowl, cream the remaining softened butter and peanut butter until smooth. Gradually beat in the powdered sugar and vanilla until incorporated and the mixture is stiff.
  7. Adjust and Chill: Add milk or cream, 1 tablespoon at a time, until the mixture is thick, stiff, and holds its shape well. Transfer the mixture to a piping bag fitted with a large round tip and chill in the refrigerator for 15–20 minutes to firm up slightly.
  8. Hollow the Cakes: Using a small knife or apple corer, carefully scoop out the centre of each cooled cupcake, leaving a cavity about 1 inch deep.
  9. Fill and Dome: Pipe or spoon a generous amount of the chilled peanut butter mixture into the cavity of each cake. Then, pipe the remaining mixture on top of the filled cavity, creating a neat, dome-shaped mound (the 'buckeye' shape). Place the assembled cupcakes back in the refrigerator while preparing the glaze (5–10 minutes).
  10. Make the Glaze: Melt the dark chocolate and coconut oil/shortening in a small, deep bowl over a double boiler or in short bursts in the microwave, stirring until perfectly smooth and glossy.
  11. Dip and Finish: Holding the cupcake by the liner, dip only the peanut butter mound into the melted chocolate glaze. Rotate slowly to ensure the glaze covers the top but leaves a collar of peanut butter visible around the base (like a proper buckeye candy).
  12. Set: Place the glazed cupcakes back on the cooling rack or a tray lined with parchment paper. Allow the chocolate to set completely (about 15 minutes at room temperature, or 5 minutes in the fridge).