Preheat the oven to 175°C. Grease and line a 9x9 inch baking pan. In a large mixing bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt. Add in the egg, buttermilk, and vegetable oil. Mix until smooth. Gradually add hot water and vanilla. Stir to combine. Pour the batter into the prepared pan and bake for 30 minutes, or until a toothpick comes out clean. Cool completely.

In a medium bowl, beat the butter until creamy. Add powdered sugar gradually. Mix in heavy cream, vanilla, and salt. Beat until light and fluffy.

Crumble the cooled cake into a large bowl until fine. Add 3–4 tablespoons of frosting and mix with your hands until the mixture is moist but not sticky. Roll into 1-inch balls and place on a parchment-lined tray. Chill in the fridge for 30–60 minutes.

Melt a small amount of candy melts. Dip the tip of each lollipop stick into the melt, then insert it halfway into each cake ball. This helps secure the stick. Chill for another 15 minutes to set.

Melt the remaining candy melts with vegetable shortening (if using) in a deep bowl. Dip each cake pop into the melts, swirling gently. Tap off excess coating and immediately decorate with sprinkles. Stick each pop upright into a foam block or stand to dry.