Preheat oven to 350º.
In large bowl, beat butter and sugar with electric mixer until light and fluffy. Beat in egg and vanilla.
Mix flour, baking powder and salt; add to butter mixture 1 cup at a time, mixing after each addition.
Do not chill dough. Divide dough into 2 balls.
On floured surface, roll each ball into a circle approximately 12 inches in diameter by 1/8 inch thick.
Dip cookie cutter in flour before each use.
Bake cookies on ungreased or parchment-lined cookie sheet 8 to 11 minutes or until cookies are lightly browned.
Allow cookies to cool before decorating.