Preheat oven to 180 degrees C. Grease baking trays.
In a large bowl, cream together the butter and brown sugar. Beat in the eggs and vanilla essence until well blended. Combine the flour, bicarb soda, baking powder and salt then stir into the creamed mixture.
On a lightly floured surface, roll the dough out to 5mm thickness. Cut into desired shapes with biscuit cutters. Place biscuits 4cm apart on baking trays.
Bake for 8 to 10 minutes in the preheated oven. Allow biscuits to cool on baking tray for 5 minutes before removing to a wire rack to cool completely. Decorate with your favourite icings or sprinkles if you like.