Mix together butter, dry Jell-o powder and vanilla and then add flour, baking powder and salt, mixing well. Place dough in plastic wrap, it will be soft. Chill dough 30 minutes in refrigerator.Using 1/2 the dough(put other 1/2 back in fridge.)Pinch small walnut-size pieces of dough and place on lightly greased cookie sheet, 2 inches apart and flatten slightly with bottom of a glass dipped in sugar or you can roll out 1/4-inch thick and cut shapes with cookie cutter. Bake in 375^ oven for 8-10 minutes, until just lightly brown on edges. Let cool on cookie sheet 1 minute before removing to rack to cool completely. These are very delicate, and crisp up as they cool.
This dough can be made in 2 batches one batch with one color of jello another with a contrasting color.
roll each color into a log and press them together - then wrap and roll in plastic wrap and chill at least 30 minutes. When ready to bake slice off cookies 1/4 inch thick and place at least 2 inches apart on greased cookie sheet. Bake as above.This way they make cute Gingham cookies. Making about 5 dozen cookies.