With the rack in the middle position, preheat the oven to 180°C (350°F). Line a baking sheet with parchment paper.
In a bowl, combine the flour, baking powder, cocoa and salt. Set aside.
In another bowl, cream the butter, sugar and vanilla using an electric mixer. Add the eggs one at a time and beat until smooth. On low speed, mix in the dry ingredients. Cover and refrigerate for at least 4 hours or place in the freezer for 1 hour.
Spread the icing sugar on a plate. Set aside.
With your hands, shape 15 ml (1 tablespoon) of the dough into a ball and coat with icing sugar, shaking to remove any excess sugar. Place on the baking sheet. Repeat for the remaining dough.
Bake for 10 to 12 minutes.
Immediately after taking the baking sheet out of the oven, spear each ball with a lollipop stick. Transfer to a rack and let cook completely.