Prepare Ganache: In a small saucepan, heat 1/2 cup of heavy whipping cream over medium heat until it just begins to boil. Pour the hot cream over 1 cup of semi-sweet chocolate chips in a bowl, letting it sit for 2 minutes before stirring until smooth. Chill the ganache mixture in the fridge until it’s firm enough to scoop, about 30 minutes. Once set, divide into 17 portions and place in the freezer for precise baking later.

Make Cookie Dough: In a medium bowl, whisk together 1 cup of all-purpose flour, 1/3 cup of Dutch process cocoa powder, 1/2 teaspoon of baking powder, and a pinch of salt until well combined. Set this dry mixture aside as you prepare the wet ingredients.

Cream Mixture: In a large mixing bowl, beat together 1/2 cup of softened unsalted butter, 1/2 cup of light brown sugar, and 1/4 cup of granulated white sugar using an electric mixer on medium speed. Continue mixing for about 2 minutes, or until the mixture is fluffy and light in color.

Incorporate Wet Ingredients: Add 2 egg yolks and 1 teaspoon of vanilla extract to the fluffy butter mixture and beat on low speed until well combined, roughly 1 minute.

Combine Dry Ingredients: Gradually add the prepared dry flour mixture to the wet ingredients, mixing on low speed until just combined.

Assemble Cookies: Using a cookie scoop, portion out the dough and flatten each ball slightly in your palm. Place a frozen ganache portion in the center of the dough and fold the edges over it, sealing it tightly.

Bake: Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper. Place 6 assembled cookies on each sheet and bake for 10 to 11 minutes.

Cool and Serve: Once baked, allow the cookies to cool on the baking sheets for about 10 minutes. Transfer the cookies to a wire rack for further cooling. Dust with powdered sugar before serving.