Whisk together flour, cocoa powder, baking powder, and salt in a medium bowl. Set aside.

Using a hand mixer, mix oil, brown sugar, eggs, and vanilla. Slowly mix in dry ingredients. The dough is very wet.

Chill the bowl of cookie dough for at least 30 minutes, or until scoopable and rollable without falling apart.

Preheat oven to 350°F. Line two cookie sheets with parchment paper or silicone mats.

Place powdered sugar in a small bowl. Scoop 1 to 2 tablespoon balls of dough, roll in powdered sugar, then place on prepared cookie sheets.

Bake for about 7 to 10 minutes, rotating pans halfway through baking.