Preheat oven to 350 degrees F (180 degrees C).
Line two 24-cup mini muffin pans with paper liners.
In a medium bowl, whisk together All-Purpose Flour (1 cup), Baking Powder (1/2 teaspoon) and Fine Salt (1/4 teaspoon).
In a large bowl with an electric mixer, beat together Natural Peanut Butter (1/2 cup), Unsalted Butter (6 tablespoon), Brown Sugar (1/2 cup), Egg (1) and the yolk of another Egg (1) on high until pale and fluffy, for about 3 minutes.
With mixer on low, beat in flour mixture, Buttermilk (1/4 cup) and pure Pure Vanilla Extract (1/4 teaspoon) until well combined.
With the large end of a melon baller or a spoon, place 2 teaspoons batter into each muffin cup, then press a Mini Dark Chocolate Peanut Butter Cups (to taste) into the center.
Bake for about 10 minutes.
Immediately place a piece of Candy Corn (to taste) on top.
Place the cupcakes on wire racks to cool completely before serving.