Add all dry ingredients to a bowl (flour, cocoa powder, sugar, baking soda, baking powder and salt), and mix them well.
Add the egg, milk and vegetable oil and mix well.
Pour the batter into the cake pop maker (fill them about 1 mm from the top). Bake them for around 4-5 minutes (You can test with a toothpick. If it comes out dry, they are ready).
Place a metal bowl over a pot of simmering water (double-boiler style) and add the butter and chocolate. Melt the chocolate/butter mix completely until smooth and shiny.