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

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

Add the large egg and mix until fully incorporated.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually sift into the butter mixture and mix on low speed until a sticky dough forms.

Divide the dough into 3-4 equal portions and mix in 1-2 tablespoons of Jello into each portion until evenly incorporated.

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

Roll each portion into 1-inch balls, then roll in additional granulated sugar before placing them on the prepared baking sheets.

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

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