For the Chocolate Ganache

1. Get a small baking sheet ready by covering it with parchment paper.
2. Place the semi-sweet chocolate chips into a small bowl.
3. Gently heat the heavy cream in the microwave or on your stove until it is just about to boil.
4. Pour the hot cream over the chocolate chips in the bowl. Let it sit undisturbed for one minute. Then, stir it well until the cream and melted chocolate are smoothly combined.
5. Put the ganache into the refrigerator. Chill it for 10 to 15 minutes until it is firm enough to scoop easily.
6. Use a small cookie scoop to portion the chilled ganache into 17 equal balls. Place these little balls onto the prepared baking sheet. Put the sheet into the freezer. Freeze the ganache balls until they are completely solid and very firm.

For the Chocolate Cookies

1. Preheat your oven to 350 degrees Fahrenheit. Prepare two baking sheets by lining them with parchment paper.
2. In a medium bowl, combine the all-purpose flour, Dutch process cocoa powder, baking powder, and salt. Give them a quick mix. Set this dry ingredient mixture aside.
3. In a large mixing bowl, add the softened unsalted butter, light brown sugar, and granulated white sugar. Use an electric hand mixer on high speed (or a stand mixer with a paddle attachment) to cream them together. Mix until the mixture is light and fluffy. This should take about two minutes.
4. Add the egg yolks and the vanilla extract to the butter and sugar mixture. Mix with the electric mixer on medium speed for one minute. The mixture should look pale and fluffy.
5. Add the dry ingredients mixture to the wet ingredients. Mix on low speed just until everything is combined. Be careful not to overmix the cookie dough.
6. Use a large, two-tablespoon cookie scoop to divide the dough into 17 equal portions. Roll each portion into a ball shape. Gently flatten out each ball slightly.
7. Take one frozen ganache ball. Place it in the center of a flattened cookie dough portion. Carefully wrap the cookie dough up and around the ganache ball. Pinch the edges firmly to seal the ganache completely inside. Roll the dough back into a smooth ball shape. Make sure the ganache is fully enclosed by the cookie dough.
8. Place the formed cookie dough balls onto the prepared baking sheets. Leave some space between them as they will spread a little. Bake about six cookies at a time on each sheet. Bake them for 10 to 11 minutes.
9. Allow the baked cookies to cool on the baking sheet for 10 minutes. Then, carefully transfer the slightly cooled cookies to a wire rack to finish cooling completely. Let them cool for another five minutes or until they are cool enough to hold comfortably. Right before serving, sprinkle the tops generously with powdered sugar for a beautiful finish. Enjoy these warm or at room temperature!