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

In a large bowl, cream together softened butter and granulated sugar using an electric mixer until light and fluffy, about 2-3 minutes.

Add in the egg and beat until fully incorporated, about 1 minute.

In a separate bowl, whisk together flour, baking powder, and salt. Gradually mix into the wet ingredients until a soft dough forms.

Divide dough into 3-4 portions and mix in 1-2 tablespoons of different Jello flavors until evenly colored.

Chill the dough in the refrigerator for 15-20 minutes to prevent spreading.

Roll chilled dough into 1-inch balls and coat lightly in additional sugar before placing on baking sheets.

Flatten each ball slightly with your palm and bake for 8-10 minutes until edges are set.

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