Preheat oven to 350°F.
Cream butter until light and fluffy, about 3 minutes.
Add powdered sugar and vanilla and mix until combined.
Mix in cornstarch and salt.
Add flour a little bit at a time. Beat until just combined.
Place dough into a cookie press and press onto an ungreased pan. Add sprinkles or colored sugar if desired.
Bake 9-11 minutes or just until done.
Immediately transfer to a wire rack to cool.
Cool and then transfer to an airtight container. Store at room temperature at least 24 hours before serving.
