In a mixing bowl, cream together the softened unsalted butter, granulated sugar, and brown sugar until light and fluffy. Add the egg and vanilla extract, mixing until well combined.

In another bowl, combine the all-purpose flour, unsweetened cocoa powder, baking soda, salt, and espresso powder (if using). Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Wrap the chocolate cookie dough in plastic wrap and place it in the fridge for about 30 minutes.

In a separate mixing bowl, cream the softened butter with granulated and brown sugars. Add the egg and vanilla extract, stirring until smooth.

In another bowl, combine the all-purpose flour, baking soda, salt, and raspberry powder or food coloring. Mix the dry ingredients into the wet mixture until fully incorporated.

Once the chocolate dough is chilled, scoop tablespoon-sized balls of each dough. Flatten each ball slightly and press a well in the center of each chocolate dough ball.

Preheat the oven to 350°F (175°C). Line your baking sheets with parchment paper. Place the chocolate dough balls on the baking sheets, and then carefully place the pink dough on top of the chocolate dough, covering it completely.

Bake the cookies for 10 to 12 minutes. Remove them from the oven and gently press down the centers again to create a well for the ganache. Allow the cookies to cool completely on a wire rack.

Heat the heavy cream in a small saucepan until just boiling. Remove from heat and pour it over the chopped chocolate chips in a bowl. Let it sit for a minute, then stir until smooth. Add the butter for an extra creamy texture if using.

Once the cookies are completely cool, fill the wells with the chocolate ganache.

Decorate as desired with freeze-dried raspberries, chocolate squares, heart sprinkles, or drizzle melted white chocolate on top.

Allow the ganache to set at room temperature or place the cookies in the fridge for a few minutes to help firm up the ganache.