In the bowl of a stand mixer, mix together the sugar and oil. Add in the eggs one at a time, mixing until fully incorporated. Stir in the vanilla.
In a seperate bowl, mix together the cocoa powder, flour, baking powder, salt. Slowly add into the wet ingredients, mixing until fully combined.
Cover, and place in the refrigerator for at least 6 hours.
Preheat the oven to 350˚F. Line 2 cookie sheet with parchment paper.
Using a cookie scoop, scoop the cookie dough onto the cookie sheets. Bake in the preheated oven for 12-14 minutes. Remove from oven and allow to cool on cookie sheet for around 5 minute. While cooling, press the candy eyeballs into the cookies. After 5 minutes, transfer to wire racks to cool completely.