1. Prepare the Crust:

1. Preheat oven to 350°F (175°C) and line baking sheets with parchment paper.
2. In a large bowl, cream together butter and sugar until light and fluffy. Beat in egg and vanilla extract.
3. In a separate bowl, whisk together flour, baking powder, and salt. Gradually add to the butter mixture, mixing until combined.
4. Divide dough into 3 equal portions. Mix each portion with one package of Jello powder until fully incorporated.
5. Roll dough into 1-inch balls, then roll each ball in granulated sugar. Place on prepared baking sheets, spacing 2 inches apart.
6. Bake for 10-12 minutes or until edges are lightly golden. Let cool on baking sheets for 5 minutes before transferring to wire racks.