With an electric mixer, cream together the butter, brown sugar, and granulated sugar until fluffy.
Beat in the egg, then mix in the vanilla and spiced apple cider packets.
In a medium-sized bowl, whisk together the flour, baking powder, cinnamon, and salt. Gradually add to the sugar and butter mixture and mix until incorporated.
Divide the dough in half and wrap each portion in plastic wrap. Refrigerate for 1 hour.
Lightly sprinkle work surface with flour and roll out dough to about 1/4-inch thickness. If dough is too hard, allow to sit at room temperature for 15 minutes. Cut out desired shapes and place on a parchment-lined baking sheet.
Refrigerate cut-out shapes while the oven preheats to 375 degrees (F).
Bake cookies at 375 degrees (F) for 9 - 11 minutes, just until the edges turn golden-brown.
Allow the cookies to cool on the baking sheet for 5 minutes, then remove to a wire rack and cool completely before decorating.