Mix Dry Ingredients: In a medium bowl, whisk together the flour, Dutch process cocoa powder, salt, and baking powder. Set aside.

Cream Butter & Sugars: In a large bowl, beat the softened butter, brown sugar, and white sugar on high speed for 2-3 minutes until light and fluffy.

Add Wet Ingredients: Add the egg and vanilla extract. Beat on medium speed until smooth and creamy, scraping down the sides as needed.

Combine & Chill: With the mixer on low, gradually add the flour mixture until just combined (don't overmix!). Cover the bowl with plastic wrap and **refrigerate for at least 30 minutes**.

Shape & Indent: Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper. Scoop 1-tablespoon dough balls and roll them smooth. Space them 2 inches apart. Use your thumb or a rounded teaspoon to press a deep indentation into the center of each ball.

Bake: Bake for 10-12 minutes. The edges should be set and tops slightly dry but soft. Let cool on the baking sheet for 5 minutes before transferring to a wire rack.

Make Ganache: Place chopped chocolate in a heatproof bowl. Simmer the heavy cream (don't boil!) and pour it over the chocolate. Let sit for 1 minute, then whisk gently until smooth. Stir in the cherry preserves.

Fill & Serve: Spoon the ganache into the cooled cookie indentations. Top with sprinkles if desired. Let set for 15 minutes before serving.