Begin by combining the granulated sugar, cocoa powder, oil, vanilla, and eggs in a large mixing bowl. Whisk thoroughly until you achieve a smooth, cohesive mixture.

In a separate bowl, whisk together the flour, baking powder, and salt until evenly blended.

Gradually incorporate the dry ingredients into the cocoa mixture, stirring just until a soft dough forms.

Cover the dough tightly with plastic wrap, then refrigerate it for a minimum of 3 hours, or allow it to chill overnight for best results.

When ready to bake, preheat your oven to 350°F (175°C). Prepare a baking sheet with parchment paper. Use a small ice cream scoop or spoon to portion the dough, creating 20 evenly-sized cookies. With dampened hands, roll each portion into a smooth ball, then coat each ball generously in powdered sugar until fully covered.

Arrange the cookie balls on the baking sheet, ensuring there’s ample space between each one for spreading.

Bake the cookies for 10-12 minutes, adjusting slightly based on the size. The cookies will emerge from the oven soft but will firm up as they cool.

Allow the cookies to cool slightly on the baking sheet before transferring them to a wire rack to cool completely.