Preheat oven to 350.
In a large bowl, whisk together flour and baking powder. Set aside.
In another large bowl, cream together butter and sugar until fluffy.
Scrape down bowl and add vanilla and egg. Beat until blended.
Add flour and beat until fully incorporated.
Mixture, when pressed together, should have the consistency of Playdoh. If necessary add water in very small increments.
Form dough into a ball and place on parchment paper.
Place another piece of parchment paper on top and roll to about 1/4" thickness.
Remove top sheet of parchment paper and place on baking sheet.
Use cookie cutter to cut out cookies and transfer to parchment line baking sheet.
Gather trimmings and reroll to make more cookies.
Bake for 8-10 minutes until center of cookie looks puffed and bottom edge of cookie is just starting to show color.
Remove and allow to cool.
Ice and decorate as desired.