Preheat your oven to 350°F (175°C).
In a bowl, whisk together flour, baking soda, and salt. Set aside.
In a separate bowl, cream together softened butter, brown sugar, and granulated sugar until light and fluffy.
Beat in the egg and vanilla extract until well combined.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Use a tablespoon or cookie scoop to drop cookie dough onto a baking sheet lined with parchment paper, spacing them about 2 inches apart.
Bake in the preheated oven for 10-12 minutes, until the edges are lightly golden.
Let the cookies cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
Once cooled, take a generous scoop of ice cream and place it between two cookies, gently pressing together.
Wrap each sandwich in plastic wrap and freeze for at least 30 minutes before serving.