Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
Cream together the softened butter with ¾ cup granulated sugar and ¾ cup powdered sugar on medium speed until pale and fluffy, about 3 minutes.
Beat in the vanilla extract and thawed Cool Whip until silky smooth, scraping the bowl as needed.
In a separate bowl, whisk the flour, baking powder, and salt.
Gently fold the dry ingredients into the wet until no streaks of flour remain.
Use a 1½-tablespoon scoop to portion the dough, then roll each mound into a smooth ball.
Roll each ball in the ¼ cup granulated sugar to coat evenly.
Arrange the balls 2 inches apart on the prepared sheets and bake for 9–10 minutes, until edges are just set and centers appear soft.
Let the cookies rest on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Notes
In my first test, I noticed that overwhipping the butter made the dough too loose—so I stopped once it looked glossy but still held its shape.During baking trials, pulling cookies out at exactly 9 minutes gave tender centers while 10 led them slightly firmer; adjust based on your oven’s heat spots.When freezing leftover cookies, I discovered packing them in single layers with parchment prevents sticking—let them thaw at room temperature for 10 minutes before serving.