Preheat oven to 350 degree F. Line cookie sheet with silicon baking mat or parchment paper.

In a mixing bowl using an electric mixer, beat butter and then add sugar and continue beating until light and fluffy.

Add the egg and vanilla. Mix until well blended.

In a separate bowl, shift together the flour, baking powder and salt. Stir into the butter mixture until well blended.

Drop dough by teaspoonful at a time onto the prepared cookie sheet, leaving 2 inches space between cookie dough. Flatten each dough with the palm of your hand.

Bake for 12 to 15 minutes or until edges of the cookies are golden brown. Immediately transfer cookies on cooling racks.