Mix the dry ingredients:

In a medium bowl, whisk together flour, cocoa powder, baking powder, and salt until well combined.

Beat the wet ingredients:

In a large bowl, whisk sugar and oil until combined. Add eggs one at a time, mixing until smooth and glossy. Stir in vanilla and peppermint extract. The batter will look shiny and thick.

Combine wet and dry:

Slowly fold the dry ingredients into the wet mixture until just combined. The dough will be sticky and dense, almost brownie-like.

Chill the dough:

Cover the bowl with plastic wrap and refrigerate for at least 2 hours (or overnight). This step is crucial for making the dough firm enough to roll and ensuring the cookies develop deep crinkles.

Preheat oven:

When ready to bake, preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.

Shape and roll:

Scoop 1 tablespoon of dough and roll into a ball (about 1 inch). First roll each ball in granulated sugar, then generously in powdered sugar. This double-coating helps the crinkle pattern form beautifully.

Bake:

Place dough balls 2 inches apart on prepared baking sheets. Bake for 10–12 minutes, until the tops are crackled and the centers look slightly underbaked.

Tip: Don’t overbake—the cookies will continue to set as they cool, keeping the insides fudgy.

Cool:

Let cookies rest on the baking sheet for 2 minutes before transferring to a wire rack. They should be soft in the middle with a crisp, sugary coating.

Serve and enjoy:

Enjoy warm with a glass of milk or let them cool completely before storing.