Preheat Oven:
Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
Make Cookie Dough:
In a large bowl, cream together butter, granulated sugar, and brown sugar until light and fluffy. Beat in eggs and vanilla extract.
Combine Dry Ingredients:
In a separate bowl, whisk together flour, cocoa powder, baking soda, and salt. Gradually add dry ingredients to wet mixture, mixing until combined.
Shape Cookies:
Scoop dough into 2-tablespoon portions and roll into balls. Place on prepared baking sheets, spacing about 2 inches apart. Flatten slightly with the bottom of a glass or your hand.
Bake:
Bake for 10–12 minutes, or until cookies are set but still soft. Allow to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
Assemble Sandwiches:
Place a scoop of slightly softened ice cream on the flat side of one cookie. Top with another cookie, pressing gently to spread ice cream evenly.
Optional Finishing Touch:
Roll edges in chocolate chips or sprinkles if desired. Wrap individually in parchment or plastic wrap and freeze for at least 1 hour before serving.