In the bowl of a food processor, process the pistachios until they are finely ground. Remove any pieces too large to fit through the openings of the cookie press discs.
In a medium bowl, combine ground pistachios, flour, and baking powder. In a large bowl, beat butter and sugar with an electric mixer on medium-high speed until light and fluffy.
Add egg, milk, extracts, and color; Mix well. Gradually add flour to the butter mixture, mixing to make a smooth dough. Do not chill the dough.
Place dough into the cookie press and press cookies onto an ungreased cookie sheet.
Bake for 10-12 minutes, or until lightly browned around the edges. Remove cookies from cookie sheet; cool on cooling rack.