Begin by chopping the dark chocolate into small pieces and placing it in a microwave-safe bowl with the unsalted butter. Heat the mixture in the microwave on medium power for 30-second intervals, stirring in between, until melted and smooth. This should take about 1 to 2 minutes total. Set aside to cool slightly before using.

In a stand mixer, beat the large eggs and sugar together on high speed until they triple in volume and turn light in color, which usually takes around 10-15 minutes. Once fluffy, gently fold in the cooled chocolate and butter mixture along with the vanilla extract.

In a separate bowl, sift together the all-purpose flour, baking powder, and salt to ensure even distribution. Gradually mix the dry ingredients into the wet chocolate mixture until you no longer see streaks of flour.

Cover the cookie dough tightly with plastic wrap or place it in an airtight container. Chill in the refrigerator for at least 4 hours, or ideally overnight.

When ready to bake, preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

Using a cookie scoop or your hands, form the chilled dough into balls about 1 inch in diameter. Roll each ball thoroughly in powdered sugar, ensuring they’re well-coated. Space them 2 inches apart on the prepared baking sheet.

Place the baking sheet in the preheated oven and bake the cookies for 12-15 minutes. Keep an eye on them; they should have a crisp exterior but remain soft in the center.

Once baked, remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes before transferring them to a wire rack.