Preheat your oven to 350°F (175°C). Grease and flour an 8×8 inch baking pan or line it with parchment paper.

In a medium bowl, sift together the flour, cocoa powder, baking powder, baking soda, salt, and espresso powder. Set aside.

In a large bowl, beat eggs, granulated sugar, and brown sugar until light and fluffy. Add sour cream, milk, vanilla extract, and vegetable oil, mixing well to combine.

Gradually add the dry ingredients to the wet mixture, mixing on low speed just until combined.

Slowly stir in the hot water or coffee to the batter until smooth and well incorporated. The batter will be thin.

Pour batter into the prepared pan and bake for 28–30 minutes, or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely on a wire rack.

Beat softened butter until creamy. Gradually add powdered sugar and cocoa powder, alternating with heavy cream and milk. Beat until smooth and spreadable. Add vanilla extract and mix well.

Crumble the cooled cake into a large bowl. Add frosting a little at a time and mix until the mixture holds together but is not too wet. Roll into 1-inch balls and place on a baking sheet lined with parchment. Insert cake pop sticks into each ball and chill in the fridge for at least 1 hour.

Melt white candy melts with vegetable shortening in a microwave-safe bowl (stir every 30 seconds until smooth). Dip each cake pop into the melted coating, tap off excess, and decorate with sprinkles or mini chocolate chips. Place upright in a styrofoam block or stand until set.