In a medium bowl, whisk together 2 cups of all-purpose flour, ¾ cup of Dutch-process cocoa powder, 1 teaspoon of baking powder, and ½ teaspoon of sea salt. Set aside.

In a large mixing bowl, beat together ½ cup of softened unsalted butter, ½ cup of light brown sugar, and ¼ cup of granulated white sugar until light and fluffy (3-4 minutes).

Add 2 large egg yolks and 1 teaspoon of vanilla extract to the creamed butter and sugar mixture. Beat until fully incorporated.

Gradually mix in the dry ingredients until just combined. Be careful not to overmix; the dough should be soft and slightly sticky.

Scoop tablespoon-sized portions of dough, roll them into balls, and place them on a baking sheet lined with parchment paper. Create an indentation in the center of each ball with your thumb and refrigerate for at least 1 hour.

Preheat your oven to 350°F (175°C). Bake the cookies for 10-11 minutes until the edges are set and the centers remain slightly soft.

To make the ganache, heat ½ cup of heavy cream until it begins to boil. Pour it over 6 ounces of chopped dark chocolate in a bowl and let sit for 2-3 minutes. Stir until smooth, then mix in 2 tablespoons of cherry preserves.

Fill each thumbprint with the ganache and chill in the refrigerator for 10-15 minutes to set.