Preheat the Oven: Heat the oven to 350°F (175°C) and line baking sheets with parchment paper.
Mix Dry Ingredients: In a bowl, whisk together flour, cocoa powder, baking soda, and salt. Set aside.
Cream Butter and Sugar: Beat softened butter and granulated sugar until light and fluffy.
Add Wet Ingredients: Beat in the egg and vanilla extract until well combined.
Add Dry Ingredients: Gradually mix in the dry ingredients until a dough forms.
Add Chocolate Chips: Stir in semi-sweet and milk chocolate chips.
Form Cookie Dough: Roll tablespoon-sized portions of dough into balls and flatten slightly on the baking sheets.
Make the Ganache: In a saucepan, heat heavy cream and ground coffee until it just simmers.
Make Ganache: Pour the hot cream over dark chocolate chips, whisking until smooth. Stir in vanilla extract.
Assemble the Cookies: Spoon a small amount of ganache into the center of each cookie dough ball. Gently press another dough ball on top.
Bake the Cookies: Bake for 12-15 minutes. Cool on a rack before serving.