Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt. Set aside.
In a separate large bowl, combine the granulated sugar, brown sugar, and vegetable oil. Mix until well blended.
Add the eggs one at a time to the sugar mixture, ensuring that each is fully incorporated before adding the next. Stir in the vanilla extract and peppermint extract (if using).
Gradually mix the dry ingredients into the wet ingredients until fully combined and the dough is smooth. It's okay if it’s a little sticky.
Chill the dough in the refrigerator for about 30 minutes to firm up slightly (optional, but helps with handling).
Once chilled, scoop about a tablespoon of dough and roll it into a ball.
Roll each ball in powdered sugar until well coated. Place the balls on the prepared baking sheet about 2 inches apart.
Gently press down each ball to flatten slightly, then sprinkle with green sprinkles for extra 'Grinch' flair.
Bake for 10-12 minutes or until the edges are set and the tops are crinkled. Allow them to cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.
Notes
Serve these festive cookies in a fun holiday-themed platter, and display some on a cake stand for added height. You may also dust a few with extra powdered sugar for a snowy effect!