Begin by melting dark chocolate and heavy cream together in a double boiler. Stir gently until fully combined and smooth. Once melted, pour ganache into a bowl and refrigerate for about 1 hour or until set.

In a mixing bowl, cream together softened unsalted butter, granulated sugar, and light brown sugar using an electric mixer until light and fluffy, roughly 2-3 minutes. Next, add the egg and vanilla extract, mixing until fully blended and creamy.

In a separate bowl, whisk together all-purpose flour, cocoa powder, baking soda, and salt until well combined. Gradually fold the dry mixture into the wet ingredients using a spatula, ensuring not to overmix.

Cover the cookie dough with plastic wrap and refrigerate for 1 hour to allow the flavors to meld and maintain shape while baking.

Remove chilled dough from the refrigerator and scoop about 1.5 tablespoons of dough. Flatten in your hand and place a small spoonful of the chilled ganache in the center. Wrap the dough around the ganache tightly.

Place the formed cookies onto a lined baking sheet and refrigerate for an additional 30 minutes to maintain shape during baking.

While the cookies are chilling, preheat your oven to 350°F (180°C).

Once preheated, bake the cookies for 10-12 minutes until edges are set while centers remain soft.

Allow cookies to cool on the baking sheet for about 5 minutes, then transfer to a wire rack. Dust with powdered sugar if desired and enjoy!