Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.

Make the chocolate dough: Beat ½ cup butter with ½ cup granulated sugar and ½ cup brown sugar until pale and fluffy, about 2–3 minutes. Add the egg and 1 teaspoon vanilla; mix until combined.

Sift together 1 cup flour, ½ cup cocoa, ½ teaspoon baking soda, ¼ teaspoon salt, and the optional ½ teaspoon espresso. Stir into the wet ingredients just until combined. Cover and chill for 30 minutes.

Make the pink dough: Repeat the creaming step with the remaining ½ cup butter, ½ cup granulated sugar, and ½ cup brown sugar. Add the egg and 1 teaspoon vanilla and mix.

Stir in 1½ cups flour, ½ teaspoon baking soda, ¼ teaspoon salt, and 2–3 teaspoons freeze-dried raspberry powder or a few drops of pink food coloring. Mix until a soft dough forms. Chill for 30 minutes.

Scoop dough into 1–1.5 tablespoon balls and place on prepared sheets about 2 inches apart. Press a shallow well into each ball with your thumb or the back of a spoon.

Bake for 10–12 minutes. The edges should be set while centers remain slightly soft. Immediately press centers again to deepen the wells. Transfer cookies to a wire rack and cool completely.

Make ganache: Place chopped chocolate in a heatproof bowl. Heat cream until it just simmers (do not boil), then pour over the chocolate. Let sit for 1 minute, then stir gently until smooth and glossy. Stir in 1 tablespoon butter if using.

Let the ganache cool until thick enough to pipe but still pourable.

Fill each cookie well with ganache using a spoon or piping bag. Top with freeze-dried raspberry crumbs, small chocolate squares, sprinkles, or a drizzle of melted white chocolate.

Let ganache set at room temperature for 30–60 minutes, or chill briefly to speed setting.