1. Prepare the Crust:

1. Preheat oven to 375°F (190°C).
2. In a large bowl, cream together the butter and sugar until light and fluffy. Add in the egg and vanilla extract and mix well.
3. Gradually add in the flour and salt, mixing until fully combined. Divide the dough into three portions. Leave one portion plain, add red food coloring to the second portion, and green food coloring to the third portion.
4. Load each colored dough into a cookie press and press the cookies onto ungreased baking sheets.
5. Bake for 8-10 minutes in the preheated oven, or until the edges are golden. Let cookies cool on the baking sheets for a few minutes before transferring to wire racks to cool completely.