In a large bowl cream together the butter and sugars until smooth. Beat in the eggs one at a time then add the vanilla. Sift together the flour, bicarbonate of soda and salt; stir into the sugar mixture. Finally mix in the chocolate chips. Drop by tablespoonfuls onto ungreased baking trays.
Bake for 8 to 10 minutes in the preheated oven or until edges are golden. Remove from baking tray to cool on cake racks.