Add the flour, baking powder, salt and espresso powder to a mixing bowl. Whisk to combine and set aside.
In a separate bowl, combine cocoa powder, granulated sugar, vanilla extract and canola oil. Mix to combine at a medium-low speed and then beat in the eggs one at a time.
Add 1/2 of the flour mixture to the wet ingredients and mix on low speed until just combined, scraping down the sides of the bowl as needed. Add remaining flour mixture and mix until just combined. Cover the mixing bowl and chill in the refrigerator for at least four hours, and up to overnight.
After chilling the dough, preheat the oven to 350°F. Line two baking sheets with parchment paper or silicone baking mats.
Scoop 1 1⁄2 tablespoons of dough from the chilled bowl and use your hands to roll into balls. Roll the balls of dough in a shallow bowl filled with the confectioners sugar before placing on the prepared baking sheets.
.Bake for 10-12 minutes. Let cookies sit on the baking sheet for five minutes before transferring to a wire rack to cool.