Preheat oven to 180 degrees C. Grease baking trays.
In a large bowl cream together the butter and sugar until smooth. Mix in the egg and vanilla. Combine the flour and baking powder; stir into the creamed mixture until blended. Divide dough into walnut sized portions. Roll each piece into a rope and then shape into a loop. Place biscuits 5cm apart on the prepared baking trays.
Bake for 8 to 10 minutes in the preheated oven until firm and golden at the edges.