Line 2 baking sheets with parchment paper.

Put chocolate and ¼ cup cocoa powder in a small heatproof bowl or glass measuring cup.

Melt butter in a skillet or saucepan over medium-low heat until bubbly but not browned, or in the microwave for 1 minute.

Pour the melted butter over the chocolate. Let the mixture sit while you whip the eggs and sugar to let the chocolate melt without stirring.

Cream the sugar, brown sugar, and salt with eggs using a mixer or hand mixer. Continue to beat for 6-8 minutes until the sugar is very light and fluffy. (The air whipped into the sugar is the only leavening in this cookie, so don’t skip this step.)

Stir the chocolate mixture until glossy and smooth. If any solid pieces remain, you can microwave the mixture in 10-seconds at a time until the mixture is perfectly smooth.

With the mixer on low speed, add the peppermint extract and the melted chocolate to the beaten sugar mixture.

Scrape the bowl well with a spatula.

Add the flour and remaining ¼ cup of the cocoa and mix on low until a few streaks of flour and cocoa remain. Use the spatula to finish folding in the dry ingredients to avoid overmixing. The dough will be looser than traditional cookie dough but not as thin as brownie batter.

Let the mixture sit in the fridge for 20 minutes to firm up slightly.

While the dough is chilling, preheat the oven to 350°

After 10 minutes, take the sheets out of the oven and bang them once or twice on the counter to create a craggy surface and dense texture.

Immediately sprinkle a bit of crushed peppermint candy in the center of each cookie and return to the oven for another 2 minutes.

Let cool completely on the baking sheets.

The cookies will keep for 4 days in an airtight container at room temperature.