Preheat your oven to 350°F and line a baking sheet with parchment paper.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and ground cinnamon.
In a separate large bowl, mix the cocoa powder, granulated sugar, and brown sugar until well combined.
Add the vegetable oil, eggs, and vanilla extract to the sugar mixture, and beat until smooth.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Chill the dough in the refrigerator for about 30 minutes to make it easier to handle.
Once chilled, scoop tablespoon-sized portions of dough and roll them into balls.
Roll each ball in powdered sugar until fully coated.
Place the balls on the prepared baking sheet, spacing them about 2 inches apart.
Bake for 10-12 minutes, or until the edges are set but the centers are still soft.
Remove from the oven and let them cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.