Preheat your oven to 350°F (175°C) and prepare your baking sheets by lining them with parchment paper.

In a large mixing bowl, combine softened unsalted butter and granulated sugar. Cream until light and fluffy, about 2-3 minutes.

Crack in one large egg into the mixture and beat until fully incorporated.

In a separate bowl, whisk together flour, baking powder, and salt. Gradually add to the wet ingredients, stirring gently until a dough forms.

Divide the dough into 3-4 portions. Add 1-2 tablespoons of different Jello flavors to each portion and mix thoroughly.

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

Roll dough into small balls about 1 inch in diameter, coat in additional sugar, and slightly flatten each ball on the baking sheet.

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

Let the cookies sit for 2 minutes on the baking sheets, then transfer to a wire rack to cool completely.