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

In a mixing bowl, cream softened unsalted butter and granulated sugar until light and fluffy.

Incorporate the large egg and mix until smooth.

In a separate bowl, whisk together all-purpose flour, baking powder, and salt. Gradually mix into the butter and sugar mixture until just combined.

Divide the dough into 3-4 portions and knead in different Jello flavors until evenly distributed.

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

Roll chilled dough into 1-inch balls, roll in additional sugar, and slightly flatten each ball.

Bake shaped cookies for 8-10 minutes until edges are set and tops are slightly crackled.

Cool cookies on the baking sheet for 2 minutes before transferring to a wire rack.