Heat the oven to 350°F and line an 8-inch square pan with parchment paper.
Whisk the flour, baking soda, and salt together in a small bowl.
Stir the melted butter, brown sugar, egg, and vanilla together until smooth.
Fold the dry ingredients into the butter mixture, then fold in three-quarters of the chocolate chips.
Press the dough evenly into the prepared pan and bake for 22 to 24 minutes, until the edges are golden and the center is just set.
Cool the cookie base completely before mixing the cream cheese and powdered sugar until smooth, folding in the whipped topping, and spreading it over the base.
Scatter the remaining chocolate chips over the topping, chill for at least 1 hour, then cut into 12 bars.