Combine the butter and sugar in a large mixing bowl. Using an electric mixer, beat on high speed until the mixture is pale and fluffy. Add the salt, egg and vanilla and beat until well combined. Using a wooden spoon or spatula, mix in the flour until thoroughly blended.
Gently form the dough into a log shape. Following the manufacturer’s instructions, fill a cookie press with the dough (you will probably need to work in several batches) and dispense the cookies at least 1 inch apart onto ungreased baking sheets.
Bake for 10 minutes, or until the cookies are lightly golden. Sprinkle with colored sugars and cool on wire racks. Store in an airtight container, up to 3 days at room temperature, 1 week refrigerated or 1 month frozen.