Preheat your oven to 350°F. Line a baking sheet with parchment paper.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy, about 2-3 minutes. Add the egg and vanilla extract, mixing until well combined.
Gradually add the dry ingredients to the wet mixture, mixing until just combined. Divide the dough into two equal portions.
In one portion of the dough, add half of the Jello powder and mix until the color is evenly distributed. In the other portion, add the remaining Jello powder and mix until combined.
Using a tablespoon, scoop out small portions of each colored dough and roll them into balls. Roll each ball in powdered sugar until fully coated.
Place the dough balls on the prepared baking sheet, spacing them about 2 inches apart. Flatten each ball slightly with the bottom of a glass or your hand.
Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden. Remove from the oven and let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.