For the Chocolate Cookies:
In a medium mixing bowl, whisk together the flour, cocoa powder, baking powder, and sea salt. Set aside.
In a large bowl, cream the softened butter, brown sugar, and granulated sugar using an electric mixer on high speed (or use a stand mixer with the paddle attachment).
Add in the egg yolks and vanilla extract. Beat on medium speed until the mixture is light and fluffy, about 1-2 minutes.
Gradually add the dry ingredients to the wet ingredients and mix on low speed until just combined.
Scoop the dough into 32 portions using a tablespoon-size cookie scoop and roll each portion into a ball. Press the center of each ball with a ¼ teaspoon to create an indent. Chill the dough for 1 hour.
Preheat the oven to 350°F (180°C). Line a large baking sheet with parchment paper.
Arrange 8 cookies per sheet and bake for 9-11 minutes (10 minutes is ideal).
After removing the cookies from the oven, press the centers again to deepen the indent if needed. Optionally, use a circular cookie cutter to shape the cookies into perfect rounds while they are still hot.
Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
For the Chocolate Cherry Ganache:
Place the chopped chocolate in a medium bowl.
Heat the heavy cream in a small saucepan until it’s just about to boil, then pour it over the chopped chocolate. Stir until smooth.
Stir in the cherry preserves until fully combined.
Assembling the Cookies:
Spoon about 1 teaspoon of ganache into the center of each cookie.
Chill the cookies in the fridge for 10-15 minutes to allow the ganache to set.
Store leftovers in an airtight container for up to 3 days.