Preheat your oven to 350°F (175°C) and line a cupcake pan with 12 liners.

In a small bowl, whisk together the all-purpose flour, Dutch process cocoa powder, baking powder, baking soda, and salt. Set aside.

In a large bowl, cream the unsalted butter and granulated white sugar together using an electric mixer on medium speed for about 2-3 minutes until light and fluffy.

Stir in the eggs and vanilla extract until the batter is pale and smooth.

Add the sour cream and whole milk until fully incorporated.

Gradually fold in the dry ingredients until just combined; do not overmix.

Scoop the batter into the liners, filling them about two-thirds full and bake for 17-20 minutes or until a toothpick comes out clean.

Let them cool in the pan for about 10 minutes before transferring to a wire rack to cool completely.

Heat the heavy cream in a saucepan until it begins to steam, then pour over the peanut butter chips and stir until smooth.

Allow the ganache to cool at room temperature until it thickens enough to pipe.

Whip the unsalted butter until fluffy, then gradually add cream cheese, powdered sugar, and creamy peanut butter until light and airy.

Core each cooled cupcake, fill with ganache, and frost with the peanut butter frosting.