Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large mixing bowl, combine softened unsalted butter with granulated sugar and beat until light and fluffy.

Add the large egg and mix until fully incorporated.

In a separate bowl, whisk together all-purpose flour, baking powder, and salt. Gradually add to the butter mixture until a dough forms.

Divide the dough into 3-4 equal portions and mix in different Jello flavors.

Wrap each dough portion in plastic wrap and chill in the refrigerator for 15-20 minutes.

Roll the chilled dough into 1-inch balls, roll each ball in additional granulated sugar, and place them on the prepared baking sheets.

Bake the cookies for 8-10 minutes until the edges are set and the tops are slightly soft.

Let the cookies cool on the baking sheets for about 2 minutes before transferring them to a wire rack to cool completely.